Cysteine & Metals or Toxic Metals

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Toxic Metals Data

Life Flow One
The Solution For Heart Disease

by
Karl Loren

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Click On The Number To View The Study
Number	Title or Description	Comment
First Section #1 through #15	Search Parameters Were: Results for your query: Search all fields for: cysteine And toxic metal Published in 1977 through 1999 Only select references with abstracts available Show references published in English only Show references pertaining to humans Documents: 1 to 15 of 15
...1...	Cysteine metabolism and metal toxicity.
...2...	Copper ions differ from other thiol reactive metal ions in their effects on the concentration and redox status of thiols in HeLa cell cultures.
...3...	Role of sulfhydryls in the hepatotoxicity of organic and metallic compounds.
...4...	CPx-type ATPases: a class of P-type ATPases that pump heavy metals [see comments]
...5...	Metallothionein induction in human peripheral blood lymphocytes by heavy metals.
...6...	Cysteine protects Na,K-ATPase and isolated human lymphocytes from silver toxicity.
...7...	A novel approach for heavy metal poisoning treatment, a model. Mercury poisoning by means of chelating microspheres: hemoperfusion and oral administration.
...8...	Effect of ascorbic, isoascorbic and dehydroascorbic acids on the growth and survival of Campylobacter jejuni.
...9...	Hepatic metallothionein as a source of zinc and cysteine during the first year of life.
...10...	Regulation of metallothionein gene expression.
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...11...	Cobalt in the environment and its toxicological implications.
...12...	Flow cytometric determination of metallothionein levels in human peripheral blood lymphocytes: utility in environmental exposure assessment.
...13...	Involvement of metallothionein and copper in cell proliferation.
...14...	Analysis of mammalian metallothionein isoforms by high-resolution SDS-gel electrophoresis.
...15...	Regulation of metallothionein production in HeLa cells.
The Reports Above Were Found with a search phrase which included: Cysteine and "toxic metal" The Reports Below Were Found with a search phrase which included: Cysteine and metal
Second Section	Search Parameters Were: Results for your query: Search all fields for: cysteine And metal Published in 1977 through 1999 Only select references with abstracts available Show references published in English only Show references pertaining to humans Documents: 1 to 100 of 248
...A1...	Factor IX Zutphen: a Cys18-->Arg mutation results in formation of a heterodimer with alpha 1-microglobulin and the inability to form a calcium-induced conformation.
...A2...	Thiol groups and reduced acidogenicity of dental plaque in the presence of metal ions in vivo.
...A3...	Antibody constant region: potential to bind metal and nucleic acid.
...A4...	Dimerization of the human papillomavirus E7 oncoprotein in vivo.
...A5...	Cysteine metabolism and metal toxicity.
...A6...	NMR analysis of the structure and metal sequestering properties of metallothioneins.
...A7...	Copper ions differ from other thiol reactive metal ions in their effects on the concentration and redox status of thiols in HeLa cell cultures.
...A8...	Affinity cleavage at the metal-binding site of phosphoenolpyruvate carboxykinase.
...A9...	Solution structure of the fourth metal-binding domain from the Menkes copper-transporting ATPase [see comments]
...A10...	Role of sulfhydryls in the hepatotoxicity of organic and metallic compounds.
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...A11...	Selective inactivation of butyrylcholinesterase with metal chelators suggests there is more than one metal binding site.
...A12...	Reversal of heavy metal resistance in multidrug-resistant human KB carcinoma cells.
...A13...	Patients with homocystinuria: high metal concentrations in hair, blood and urine.
...A14...	Purification of glycogen phosphorylase isozymes by metal-affinity chromatography.
...A15...	A structural role for metal ions in the "wild-type" conformation of the tumor suppressor protein p53.
...A16...	Immobilized metal ion affinity chromatography of serum albumins.
...A17...	Metallothionein: an exceptional metal thiolate protein.
...A18...	Combined deficiency of xanthine oxidase and sulphite oxidase: a defect of molybdenum metabolism or transport?
...A19...	An engineered cysteine in the external mouth of a K+ channel allows inactivation to be modulated by metal binding.
...A20...	Structure of mammalian metallothionein.
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...A21...	NMR analysis of the structure and metal sequestering properties of metallothioneins.
...A22...	Glutathione mercaptides as transport forms of metals.
...A23...	Induction of metallothionein mRNA in HeLa cells by dexamethasone and by heavy metals.
...A24...	Functional domains of the heavy metal-responsive transcription regulator MTF-1.
...A25...	Interaction of mammalian sperm nuclear protamines and peptides derived thereof with immobilized zinc.
...A26...	Memories of metallothionein.
...A27...	Catalase inactivation following photosensitization with tetrasulfonated metallophthalocyanines.
...A28...	113Cd nmr study of the metal cluster structure of human liver metallothionein.
...A29...	Features of structural zinc in mammalian alcohol dehydrogenase. Site-directed mutagenesis of the zinc ligands.
...A30...	The metal ion requirement for activation of latent collagenase from human polymorphonuclear leucocytes.
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...A31...	A novel cysteine-rich sequence-specific DNA-binding protein interacts with the conserved X-box motif of the human major histocompatibility complex class II genes via a repeated Cys-His domain and functions as a transcriptional repressor.
...A32...	Characterization of interactions of nitric oxide with human hemoglobin A by infrared spectroscopy.
...A33...	Mutation of the metal-bridging proton-donor His63 residue in human Cu, Zn superoxide dismutase. Biochemical and biophysical analysis of the His63-->Cys mutant.
...A34...	Proteolytic processing of Alzheimer's disease beta A4 amyloid precursor protein in human platelets.
...A35...	EEA1, an early endosome-associated protein. EEA1 is a conserved alpha-helical peripheral membrane protein flanked by cysteine "fingers" and contains a calmodulin-binding IQ motif.
...A36...	Solution structure of a cysteine rich domain of rat protein kinase C.
...A37...	Metal binding 'finger' structures in the glucocorticoid receptor defined by site-directed mutagenesis.
...A38...	Heavy metal inhibition of carnitine acetyltransferase activity in human placental syncytiotrophoblast: possible site of action of HgCl2, CH3HgCl, and CdCl2.
...A39...	Histamine as a ligand in blood plasma. Part 6. Aspartate and glutamate as possible partner ligands for zinc and histamine to favour histamine catabolism.
...A40...	Exposure of hydrophobic moieties promotes the selective degradation of hydrogen peroxide-modified hemoglobin by the multicatalytic proteinase complex, proteasome.
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...A41...	Identification of a putative antioxidant response element in the 5'-flanking region of the human gamma-glutamylcysteine synthetase heavy subunit gene.
...A42...	Tumor-promoting phorbol esters and cell proliferation stimulate secretion of basement membrane (type IV) collagen-degrading metalloproteinase by human fibroblasts.
...A43...	Immobilized-enzyme rate-determination method for glucose analysis.
...A44...	Involvement of cysteine, serotonin and their analogues in peroxidase-oxidase reactions.
...A45...	Determination and metabolism of dithiol chelating agents. VI. Isolation and identification of the mixed disulfides of meso-2,3-dimercaptosuccinic acid with L-cysteine in human urine.
...A46...	Structural and functional characterization of human immunodeficiency virus tat protein.
...A47...	The extended environment of mononuclear metal centers in protein structures.
...A48...	Thermoanaerobacter brockii alcohol dehydrogenase: characterization of the active site metal and its ligand amino acids.
...A49...	Intersubunit fluorescence energy transfer in human factor VIII.
...A50...	Quantitative investigation of copper(II) and zinc(II) complexes with S-carboxymethyl-L-cysteine and computer-simulated appraisal of their potential significance in vivo.
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...A51...	Distinct metal-thiolate clusters in the N-terminal domain of neuronal growth inhibitory factor.
...A52...	The effects of heavy metal cations and sulfhydryl reagents on degranulation from digitonin-permeabilized neutrophils.
...A53...	Protein carbonyl formation in blood plasma by cephalosporins.
...A54...	Effects of sulfhydryl regents on the activity of lambda Ser/Thr phosphoprotein phosphatase and inhibition of the enzyme by zinc ion.
...A55...	A novel MT gene of rice plants is strongly expressed in the node portion of the stem.
...A56...	Purification and characterization of a protease from Bacteroides gingivalis 381.
...A57...	Sensitivity of Escherichia coli (MutT) and human (MTH1) 8-oxo-dGTPases to in vitro inhibition by the carcinogenic metals, nickel(II), copper(II), cobalt(II) and cadmium(II).
...A58...	CPx-type ATPases: a class of P-type ATPases that pump heavy metals [see comments]
...A59...	A mutant metallothionein which has inverse fragment composition exhibits high cadmium-binding ability.
...A60...	Structure of the rainbow trout metallothionein B gene and characterization of its metal-responsive region.
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...A61...	Structure and tissue-specific expression of the human metallothionein IB gene.
...A62...	Functional constituents of the active site of human neutrophil collagenase.
...A63...	Engineering a cysteine ligand into the zinc binding site of human carbonic anhydrase II.
...A64...	N-terminal domains of human copper-transporting adenosine triphosphatases (the Wilson's and Menkes disease proteins) bind copper selectively in vivo and in vitro with stoichiometry of one copper per metal-binding repeat.
...A65...	Heteronuclear 113Cd-1H NMR study of metal coordination in the human retinoic acid receptor-beta DNA binding domain.
...A66...	Air pollution particles induce IL-6 gene expression in human airway epithelial cells via NF-kappaB activation.
..A67...	Physicochemical properties of charge isomers of recombinant human superoxide dismutase.
...A68...	A comparison of cysteine and serine proteinases in human gingival crevicular fluid with tissue, saliva and bacterial enzymes by analytical isoelectric focusing.
...A69...	Characterization of zinc-binding sites in human stromelysin-1: stoichiometry of the catalytic domain and identification of a cysteine ligand in the proenzyme.
...A70...	Induction of drug resistance to gold sodium thiomalate in a monocyte cell line, THP-1.
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...A71...	Oxidation of low density lipoprotein by thiols: superoxide-dependent and -independent mechanisms.
...A72...	Alterations of thiol metabolism in human cell lines induced by low amounts of copper, mercury or cadmium ions.
...A73...	Identification and functional requirement of Cu(I) and its ligands within coagulation factor VIII.
...A74...	Metallothionein induction in human peripheral blood lymphocytes by heavy metals.
...A75...	Metal binding properties and secondary structure of the zinc-binding domain of Nup475.
...A76...	Metal binding properties and secondary structure of the zinc-binding domain of Nup475.
...A77...	Cloning and nucleotide sequence of a complementary DNA encoding Xenopus laevis metallothionein: mRNA accumulation in response to heavy metals.
...A78...	The peptidase activity of human serum butyrylcholinesterase: studies using monoclonal antibodies and characterization of the peptidase.
...A79...	Disruption of prosomes by some bivalent metal ions results in the loss of their multicatalytic proteinase activity and cancels the nuclease resistance of prosomal RNA.
...A80...	Transient induction of the MRP/GS-X pump and gamma-glutamylcysteine synthetase by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea in human glioma cells.
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...A81...	Complexation of copper(I) by thioamino acids. Implications for copper speciation in blood plasma.
...A82...	Human papillomavirus type 16 E6 proteins with glycine substitution for cysteine in the metal-binding motif.
...A83...	Monoclonal antibodies specific for Semliki Forest virus replicase protein nsP2.
...A84...	Determination and metabolism of dithiol chelating agents. XVII. In humans, sodium 2,3-dimercapto-1-propanesulfonate is bound to plasma albumin via mixed disulfide formation and is found in the urine as cyclic polymeric disulfides.
...A85...	Physiological thiol compounds exert pro- and anti-oxidant effects, respectively, on iron- and copper-dependent oxidation of human low-density lipoprotein.
...A86...	Human placenta cytidine deaminase: a zinc metalloprotein.
...A87...	In vitro study of the NS2-3 protease of hepatitis C virus.
...A88...	Sequence analysis of P gene of human parainfluenza type 2 virus: P and cysteine-rich proteins are translated by two mRNAs that differ by two nontemplated G residues.
...A89...	Cysteine protects Na,K-ATPase and isolated human lymphocytes from silver toxicity.
...A90...	The solution structure of the amino-terminal HHCC domain of HIV-2 integrase: a three-helix bundle stabilized by zinc.
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...A91...	The cysteine-rich domain of human proteins, neuronal chimaerin, protein kinase C and diacylglycerol kinase binds zinc. Evidence for the involvement of a zinc-dependent structure in phorbol ester binding.
...A92...	Cysteine mapping in the ion selectivity and toxin binding region of the cardiac Na+ channel pore [published erratum appears in J Membr Biol 1997 Mar 1;156(1):98]
...A93...	The amyloid precursor protein of Alzheimer's disease in the reduction of copper(II) to copper(I) [see comments]
...A94...	Identification of an ATPase activity associated with a 71-kilodalton polypeptide encoded in gene 1 of the human coronavirus 229E.
...A95...	The autoimmunity-inducing xenobiotic mercury interacts with the autoantigen fibrillarin and modifies its molecular and antigenic properties.
...A96...	Short related sequences in the cytoplasmic domains of CD4 and CD8 mediate binding to the amino-terminal domain of the p56lck tyrosine protein kinase.
...A97...	Metal ion and salt effects on the phospholipase A2, lysophospholipase, and transacylase activities of human cytosolic phospholipase A2.
...A98...	The mechanism of Hg2+ toxicity in cultured human oral fibroblasts: the involvement of cellular thiols.
...A99...	Maleimidocysteineamido-DOTA derivatives: new reagents for radiometal chelate conjugation to antibody sulfhydryl groups undergo pH-dependent cleavage reactions.
...A100...	Role of oxygen and metal ions in the instability of streptolysin O.

HealthGate Documents

Record 1 from database: MEDLINE
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Title: Cysteine metabolism and metal toxicity.
Author: Quig D
Address: Doctor's Data, Inc., West Chicago, IL, USA. dquig@doctorsdata.com
Source: Altern Med Rev, 1998 Aug, 3:4, 262-70
Abstract: Chronic, low level exposure to toxic metals is an increasing global problem. The symptoms associated with the slow accumulation of toxic metals are multiple and rather nondescript, and overt expression of toxic effects may not appear until later in life. The sulfhydryl-reactive metals (mercury, cadmium, lead, arsenic) are particularly insidious and can affect a vast array of biochemical and nutritional processes. The primary mechanisms by which the sulfhydryl-reactive metals elicit their toxic effects are summarized. The pro-oxidative effects of the metals are compounded by the fact that the metals also inhibit antioxidative enzymes and deplete intracellular glutathione. The metals also have the potential to disrupt the metabolism and biological activities of many proteins due to their high affinity for free sulfhydryl groups. Cysteine has a pivotal role in inducible, endogenous detoxication mechanisms in the body, and metal exposure taxes cysteine status. The protective effects of glutathione and the metallothioneins are discussed in detail. Basic research pertaining to the transport of toxic metals into the brain is summarized, and a case is made for the use of hydrolyzed whey protein to support metal detoxification and neurological function. Metal exposure also affects essential element status, which can further decrease antioxidation and detoxification processes. Early detection and treatment of metal burden is important for successful detoxification, and optimization of nutritional status is paramount to the prevention and treatment of metal toxicity.
Language of Publication: English
Unique Identifier: 98404750

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MeSH Heading (Major): Arsenic|ME/*PO; Cysteine|DE/*ME; Metals, Heavy|ME/*PO
MeSH Heading: Chronic Disease; Endocrine Glands|DE; Human; Leucine|ME; Mercury|ME; Mercury Poisoning|ME/TH; Oxidation-Reduction|DE; Poisoning|TH

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
ISSN: 1089-5159
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals, Heavy); 4371-52-2 (Cysteine); 7005-03-0 (Leucine); 7439-97-6 (Mercury); 7440-38-2 (Arsenic)

Record 2 from database: MEDLINE
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Title: Copper ions differ from other thiol reactive metal ions in their effects on the concentration and redox status of thiols in HeLa cell cultures.
Author: Hultberg B; Andersson A; Isaksson A
Address: Department of Clinical Chemistry, University Hospital, Lund, Sweden.
Source: Toxicology, 1997 Feb, 117:2-3, 89-97
Abstract: Ions of metals such as copper, mercury, silver and cadmium are known to exhibit a high affinity for thiol groups and may therefore severely disturb many metabolic functions in the cell. Copper ions are also known to catalyse the formation of toxic oxygen species through a series of redox reactions. In the present study, we have determined the concentration of reduced and total glutathione, cysteine and homocysteine in a cell culture system (HeLa cell line) after addition of these metal ions. The main findings of the metal ion effect on the total thiol concentrations are that all metal ions increased the release of glutathione into the medium. Since the intracellular concentration of glutathione did not decrease under these conditions, the synthesis of glutathione must have been increased. In contrast to the other metal ions, copper ions also increased the release of homocysteine into the medium, possibly through interaction with S-adenosylhomocysteine hydrolase. The main findings of metal ion effects on reduced thiol are that, at concentrations not interfering with cell growth, mercury, silver and cadmium ions increased the concentration of extracellular reduced glutathione, possibly reflecting the increase of total glutathione in the medium. In contrast to the other metal ions, the addition of even very low amounts of copper ions (1 mumol/l) decreased the concentration of intra- and extracellular reduced thiols indicating oxidative stress.
Language of Publication: English
Unique Identifier: 97210824

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MeSH Heading (Major): Copper|*TO; Cysteine|*DE/ME; Glutathione|BI/*DE; Hela Cells|*DE/ME; Homocysteine|*DE/ME; Metals, Heavy|*TO
MeSH Heading: Animal; Cadmium|TO; Cations|TO; Human; Mercury|TO; Oxidation-Reduction; Oxidative Stress|DE; Silver|TO; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0300-483X
Country of Publication: IRELAND

Record 3 from database: MEDLINE
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Title: Role of sulfhydryls in the hepatotoxicity of organic and metallic compounds.
Author: Klaassen CD; Bracken WM; Dudley RE; Goering PL; Hazelton GA; Hjelle JJ
Address
Source: Fundam Appl Toxicol, 1985 Oct, 5:5, 806-15
Abstract: Endogenous sulfhydryl compounds serve a critical role in maintaining the function and viability of living systems. Glutathione (GSH) is the most abundant of these nonprotein thiols. During the past decade it has been demonstrated that sulfhydryls such as GSH also serve an important role in protecting vital nucleophilic sites in the liver from electrophilic attack by numerous classes of reactive chemicals. Organocompounds such as bromobenzene and acetaminophen which undergo microsomal metabolism yield reactive intermediates that are specifically inactivated by conjugation with sulfhydryls in the form of GSH. Thus, for organocompounds GSH is extremely important in protecting against toxic insults. More recently, other sulfhydryl compounds also have been found to serve a specific but as yet less defined role in protecting biological systems against chemically induced injury. Metals such as cadmium have a high affinity for sulfhydryls and the metal binding protein metallothionein binds cadmium with high affinity. The highly specific association of the metal with this sulfhydryl-enriched protein serves to effectively sequester the reactive cadmium ion. The central role of sulfhydryl equivalents in the detoxication of organo- and metallocompounds is similar; however, the mechanism by which this is achieved is fundamentally different.
Language of Publication: English
Unique Identifier: 86056693

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MeSH Heading (Major): Hepatitis, Toxic|*ME; Metals|*TO; Sulfhydryl Compounds|*ME
MeSH Heading: Acetaminophen|TO; Animal; Biotransformation; Bromobenzenes|TO; Cadmium Poisoning|ME; Cysteine|PD; Cytochrome P-450|ME; Human; Metallothionein|ME; Microsomes, Liver|EN; Support, U.S. Gov't, P.H.S.; Zinc|TO

Publication Type: JOURNAL ARTICLE
ISSN: 0272-0590
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Bromobenzenes); 0 (Metals); 0 (Sulfhydryl Compounds); 103-90-2 (Acetaminophen); 4371-52-2 (Cysteine); 7440-66-6 (Zinc); 9035-51-2 (Cytochrome P-450); 9038-94-2 (Metallothionein)

Record 4 from database: MEDLINE
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Title: CPx-type ATPases: a class of P-type ATPases that pump heavy metals [see comments]
Author: Solioz M; Vulpe C
Address: Department of Clinical Pharmacology, University of Berne, Switzerland. solioz@ikp.unibe.ch
Source: Trends Biochem Sci, 1996 Jul, 21:7, 237-41
Abstract: ATP-driven heavy metal pumps represent a newly defined class of proteins that translocate toxic and essential metals across biological membranes. These transporters form a separate evolutionary branch of the ion-transporting P-type ATPases. We propose to call these enzymes CPx-type ATPases, based on the common novel feature of a conserved intramembranous cysteine-proline-cysteine or cysteine-proline-histidine motif.
Language of Publication: English
Unique Identifier: 96334292

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MeSH Heading (Major): Adenosinetriphosphatase|CH/*ME; Conserved Sequence|*; Ion Pumps|*ME; Metals|*ME
MeSH Heading: Amino Acid Sequence; Human; Molecular Sequence Data; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0167-7640
Country of Publication: ENGLAND

Record 5 from database: MEDLINE
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Title: Metallothionein induction in human peripheral blood lymphocytes by heavy metals.
Author: Yamada H; Koizumi S
Address: Department of Experimental Toxicology, National Institute of Industrial Health, Kawasaki, Japan.
Source: Chem Biol Interact, 1991, 78:3, 347-54
Abstract: Human peripheral blood lymphocytes have the capacity to produce metallothioneins (MTs) as a protective response to cadmium exposure. To define the range of metal species inducing lymphocyte MTs, cellular proteins synthesized after exposure to each of 11 heavy metals were analyzed by gel electrophoresis. Toxic metals such as cadmium, mercury and silver were found to induce thioneins (apoproteins of MTs) at relatively low concentrations (maximum at approximately 10 microM), whereas less toxic metals such as zinc, copper and nickel were inductive at relatively high concentrations (maximum at approximately 200 microM). Tin, lead, iron, cobalt, and manganese did not induce thioneins. The heavy metal specificity of MT induction in the lymphocyte resembles that in the liver, and the regulatory mechanism of MT production seems to be similar in both of these tissues. In the cells exposed to highly toxic metals such as cadmium and mercury, expression of cytotoxicity (represented by decline of cysteine uptake) was remarkable at the metal concentrations higher than those saturating thionein induction, supporting the protective role of MTs against heavy metals.
Language of Publication: English
Unique Identifier: 91300580

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MeSH Heading (Major): Lymphocytes|DE/*ME; Metallothionein|*BI; Metals|*TO
MeSH Heading: Electrophoresis, Polyacrylamide Gel; Human; Male

Publication Type: JOURNAL ARTICLE
ISSN: 0009-2797
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 0 (Metals); 9038-94-2 (Metallothionein)

Record 6 from database: MEDLINE
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Title: Cysteine protects Na,K-ATPase and isolated human lymphocytes from silver toxicity.
Author: Hussain S; Anner RM; Anner BM
Address: Laboratory of Experimental Therapeutics, Geneva University Medical Center, Switzerland.
Source: Biochem Biophys Res Commun, 1992 Dec 30, 189:3, 1444-9
Abstract: Metal-binding proteins are important components of retroviruses such as human immunodeficiency virus (HIV). Therefore, metals could be used as antiviral agents. However, most metals are toxic for humans with the exception of silver which is toxic only to prokaryotic cells and viruses. In addition, HIV infection causes a decrease in body cysteine. We formed a complex of silver and cysteine, named silver-cysteine. Healthy human lymphocytes were incubated with silver-nitrate or silver-cysteine. Negligible cell survival was seen at 50 microM silver-nitrate. However, in presence of 1 mM cysteine, the viability remained unaffected up to 1 mM of silver. Further, silver inhibition of isolated Na,K-ATPase was easily reversed by cysteine. Thus, non-toxic silver-cysteine could be used as an anti-viral and cysteine-replenishing agent.
Language of Publication: English
Unique Identifier: 93129209

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MeSH Heading (Major): Cysteine|*PD; Lymphocytes|CY/*DE; Na(+)-K(+)-Exchanging ATPase|AI/*ME; Silver|*TO
MeSH Heading: Animal; Cell Survival|DE; Human; HIV|DE; In Vitro; Kidney Medulla|EN; Kinetics; Sheep; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.6.1.37 (Na(+)-K(+)-Exchanging ATPase); 4371-52-2 (Cysteine); 7440-22-4 (Silver)

Record 7 from database: MEDLINE
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Title: A novel approach for heavy metal poisoning treatment, a model. Mercury poisoning by means of chelating microspheres: hemoperfusion and oral administration.
Author: Margel S
Address
Source: J Med Chem, 1981 Oct, 24:10, 1263-6
Abstract: The chelating drugs BAL (2,3-dimercaptopropanol), EDTA (ethylenediaminetetraacetic acid), and penicillamine (2-amino-3-mercapto-3-methylbutanoic acid), which are used for metal poisoning, are toxic and there is a real need for alternatives, especially for severe cases. A novel approach for treatment of heavy-metal poisoning is under investigation in our group. The approach utilizes the synthesis of chelating microspheres specific for the desired metallic compound. The microspheres are suggested for use in severe cases by means of hemoperfusion, as a first aid, and then by oral administration. As a model this approach was tried for mercury poisoning. Polymercaptal microspheres of 0.8 micrometer average size were synthesized. The microspheres have a high surface area, have a high affinity toward organic and inorganic mercury compounds, and can compete easily with albumin and cysteine in the ability to bind mercury compounds. These microspheres also were encapsulated with agarose--a blood compatible polymer--and were tried successfully for plasma perfusion (in 10 min, 40% of CH3HgCl and of HgCl2 were removed from 20 ppm of poisoned plasma).
Language of Publication: English
Unique Identifier: 82122390

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MeSH Heading (Major): Chelating Agents|*AD/ME; Hemoperfusion|*; Mercury Poisoning|*TH
MeSH Heading: Administration, Oral; Human; Mercury|ME; Microspheres; Models, Biological

Publication Type: JOURNAL ARTICLE
ISSN: 0022-2623
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Chelating Agents); 7439-97-6 (Mercury)

Record 8 from database: MEDLINE
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Title: Effect of ascorbic, isoascorbic and dehydroascorbic acids on the growth and survival of Campylobacter jejuni.
Author: Juven BJ; Kanner J
Address
Source: J Appl Bacteriol, 1986 Oct, 61:4, 339-45
Abstract: Ascorbic acid (AsA), added to nutrient broth at a concentration of 5 mmol/l, was bactericidal towards Campylobacter jejuni grown at 42 degrees C in a micro-aerobic atmosphere. Specific enzymes, radical scavengers, metal chelators and reducing agents were tested as possible antagonists to the cytotoxicity of AsA. The addition of catalase or of the metal chelators ceruloplasmin or Desferal did not prevent the cytotoxic effect of AsA. The addition of the hydroxyl radical scavengers mannitol, formate, histidine or DMSO also failed to counteract the toxicity of AsA. On the other hand, thiourea or cysteamine and the reducing agents cysteine or dithionite significantly increased the recovery of C. jejuni in the presence of AsA. Although the possibility of the involvement of hydroxyl radicals in AsA cytotoxicity cannot be ruled out, it appears that the toxic effect of AsA is due mostly to the formation of products of oxidation of AsA and particularly to dehydroascorbic acid (DHA). Dehydroascorbic acid was also bactericidal to C. jejuni at a concentration of 5 mmol/l. Of all the compounds tested, only cysteamine was effective in preventing (partially) the toxic effect of DHA. The growth of C. jejuni was not inhibited by the addition of 5 mmol/l of isoascorbic acid or sodium isoascorbate.
Language of Publication: English
Unique Identifier: 87056716

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MeSH Heading (Major): Ascorbic Acid|*AA/*PD; Campylobacter fetus|DE/*GD; Dehydroascorbic Acid|*PD
MeSH Heading: Human; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0021-8847
Country of Publication: ENGLAND
CAS Registry/EC Number: 490-83-5 (Dehydroascorbic Acid); 50-81-7 (Ascorbic Acid); 89-65-6 (isoascorbic acid)

Record 9 from database: MEDLINE
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Title: Hepatic metallothionein as a source of zinc and cysteine during the first year of life.
Author: Zlotkin SH; Cherian MG
Address: Department of Nutritional Sciences, Hospital for Sick Children, University of Toronto, Ontario, Canada.
Source: Pediatr Res, 1988 Sep, 24:3, 326-9
Abstract: Metallothionein, a high cysteine-containing protein, can bind with both essential and nonessential metals and thus play an important role as a metal storage protein and also in the detoxification of toxic metals. Although in the human fetus, levels of trace minerals and metallothionein are very high, their postnatal changes are not well documented. The purpose of the present investigation, therefore, was to quantify the accumulation of metallothionein in premature and full-term infants during the first year of life and to identify factors affecting its accumulation. From 47 postmortem samples, it was determined that hepatic metallothionein levels were highest in newborn premature and full-term infants falling to levels found in older children by 4.4 months of age. Hepatic zinc levels were also highest in the youngest infants, falling with increasing postnatal age. There was a significant positive correlation between zinc and metallothionein at all ages. However, there was a negative correlation between hepatic metallothionein levels and cystathionase activity. Hepatic copper and metallothionein levels were unrelated. The renal concentration of metallothionein, zinc, and copper were significantly lower than corresponding hepatic levels. The fall in hepatic levels of zinc and metallothionein during the first months of life correspond to a period of negative zinc balance and low endogenous cysteine production in the newborn. Thus metallothionein may play an important role as a storage depot for these two essential nutrients during this critical period of active growth.
Language of Publication: English
Unique Identifier: 89098117

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MeSH Heading (Major): Infant, Newborn|*ME; Infant, Premature|*ME; Liver|GD/*ME; Metallothionein|*ME; Zinc|*ME
MeSH Heading: Aging; Copper|ME; Cystathionine gamma-Lyase|ME; Female; Human; Male; Reference Values

Publication Type: JOURNAL ARTICLE
ISSN: 0031-3998
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 4.4.1.1 (Cystathionine gamma-Lyase); 7440-50-8 (Copper); 7440-66-6 (Zinc); 9038-94-2 (Metallothionein)

Record 10 from database: MEDLINE
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Title: Regulation of metallothionein gene expression.
Author: Andrews GK
Address: Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103.
Source: Prog Food Nutr Sci, 1990, 14:2-3, 193-258
Abstract: The metallothioneins are small, cysteine-rich proteins that have the capacity for high affinity binding of heavy metal ions, and whose synthesis is regulated by metal ion concentrations. These properties suggest that they play pivotal roles in the metabolism of the relatively nontoxic essential metals (zinc and copper), as well as toxic heavy metals (cadmium), a concept supported by a variety of studies of cells in culture, as well as in intact animals. Expression of the metallothionein genes may have important implications in the nutritional status of the animal, in its response to stresses (inflammation, heavy metal toxicity), and in embryonic, fetal and neonatal development. The complementary DNAs and genes that encode the metallothioneins have been cloned and analyzed from a wide variety of eukaryotes. Striking features of the metallothioneins include: their high degree of amino acid sequence similarity (including conservation in the placement of cysteine residues in the molecule reflecting their function in metal binding); a conserved tripartite gene structure; and their transcriptional induction by metal ions, as well as other hormonal and environmental stimuli. The precise mechanisms and biochemical pathways by which cells transduce environmental signals into transcriptional induction of the metallothionein genes are beginning to be defined. Recent studies indicate that metal effects are exerted via positive trans-acting factors induced to interact with cis-acting DNA sequences in the promoter, in turn leading to transcriptional induction. However, the metallothionein gene promoter is structurally complex, and contains binding sites for a variety of nuclear proteins that likely regulate basal as well as induced levels of expression of these genes. Recent studies also suggest the possible involvement of post-transcriptional processes in the regulation of metallothionein levels in the cell. Furthermore, evidence of striking differences in the levels of metallothionein gene expression among various cell types in vivo have recently been documented. Although several detailed reviews of the metallothioneins have been published recently, this review will focus, in large part, on the molecular biology of the metallothioneins, with particular emphasis on recent advances in our understanding of the mechanisms regulating expression of these interesting and important genes. Given the large volume of literature on the metallothioneins and the space limitations of this review, it is impossible to comprehensively cite the studies of each of my colleagues who have contributed so much to this field. Instead the reader is often directed to reviews of this subject for much of the earlier literature, and emphasis is placed on more current publications in this field.
Language of Publication: English
Unique Identifier: 91156807

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MeSH Heading (Major): Gene Expression Regulation|*; Metallothionein|CH/*GE
MeSH Heading: Amino Acid Sequence; Animal; Human; Molecular Sequence Data; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, ACADEMIC
ISSN: 0306-0632
Country of Publication: ENGLAND
CAS Registry/EC Number: 9038-94-2 (Metallothionein)

Record 11 from database: MEDLINE
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Title: Cobalt in the environment and its toxicological implications.
Author: Domingo JL
Address
Source: Rev Environ Contam Toxicol, 1989, 108:, 105-32
Abstract: Cobalt is an essential trace element which is widely distributed in nature. Most of cobalt consumed is used in the manufacture of alloys, and although not released extensively in the environment, it may represent a hazard to human health. In addition, excess dietary cobalt produces toxic effects in animals. Polycythemia and hyperglycemia with transitory damage to pancreatic alpha-cells have been widely reported after cobalt administration. Cobalt salts induce respiratory deficiency in yeast. CoCl2 increased sister chromatid exchange (SCE) in P388D1 cells and in lymphocytes from two donors. So far it has not been possible to induce cancer in experimental animals using cobalt by any other route than by injection. Ingestion of cobalt may lead to reproductive changes in the male rat such as loss of testicular volume and darkening of testicle color. On the other hand, oral administration of cobalt did not produce teratogenicity or significant fetotoxicity in the rat at daily doses as high as 100 mg CoCl2/kg. However, cobalt affected the period of late gestation as well as the postnatal development of the pups. Occupational toxicology of cobalt, hygienic and epidemiologic aspects, and treatment of cobalt poisoning are also topics of special interest. Cobalt is a metal with marked allergenic potential. Asthma, interstitial lung disease and combined asthma and alveolitis have been described as occupational health hazards. EDTA, DTPA, and N-acetyl-L-cysteine have been suggested as possible antidotes in cobalt intoxication.
Language of Publication: English
Unique Identifier: 89161229

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MeSH Heading (Major): Cobalt|PD/PK/*TO
MeSH Heading: Air Pollutants, Occupational|TO; Animal; Carcinogens; Chelating Agents|TU; Diet; Human; Lethal Dose 50; Mutagens; Rats; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
ISSN: 0179-5953
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Air Pollutants, Occupational); 0 (Carcinogens); 0 (Chelating Agents); 0 (Mutagens); 7440-48-4 (Cobalt)

Record 12 from database: MEDLINE
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Title: Flow cytometric determination of metallothionein levels in human peripheral blood lymphocytes: utility in environmental exposure assessment.
Author: Yurkow EJ; Makhijani PR
Address: Department of Pharmacology and Toxicology, Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey 08855-1179, USA. yurkow@rci.rutgers.edu
Source: J Toxicol Environ Health, 1998 Jul, 54:6, 445-57
Abstract: Metallothioneins (MT) are ubiquitous, low-molecular-weight proteins that exhibit high binding affinities for heavy metal ions. The expression of these cysteine-rich proteins is induced in response to various types of chemical and physical stresses and therefore can be used to assess human exposure to cytotoxic environmental agents. In the current study, MT levels of human peripheral blood lymphocytes were determined using an MT-specific antibody and flow cytometry. Treatment of human whole blood ex vivo with CdCl2 was found to induce a concentration- and time-dependent increase in lymphocyte MT levels at concentrations as low as 0.3 microM and within a 12-h period. Interestingly, differences were observed in the magnitude of cadmium-induced MT levels in the lymphocytes of six human test subjects. Two members of the study population exhibited CdCl2-induced cellular MT levels that were up to twofold greater than the lymphocytes of other human subjects. While the lymphocytes of most test subjects exhibited a symmetric (unimodal) distribution of cadmium-induced MT-specific fluorescence, the cells of two individuals displayed a heterogeneous (nonuniform) distribution of MT levels. Dual-parameter flow cytometric analysis using phenotype-specific antibodies indicated that variations in the responsiveness of subpopulations of lymphocytes to CdCl2 were responsible for the heterogeneous distribution of MT-specific cellular fluorescence. T-helper (CD4-positive) and T-suppressor/cytotoxic (CD8-positive) lymphocytes expressed higher cellular levels of MT than other lymphocyte subpopulations (i.e., B lymphocytes, natural killer cells). Our results suggest that MT protein levels of peripheral blood lymphocytes, as determined by this flow cytometric method, may be used to assess human exposure to toxic metals and to characterize various quantitative/qualitative aspects of the response of individuals to cadmium and possibly to other types of environmental stresses.
Language of Publication: English
Unique Identifier: 98324287

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MeSH Heading (Major): Environmental Exposure|*AN; Flow Cytometry|*MT; Leukocytes, Mononuclear|DE/*ME; Metallothionein|*BL
MeSH Heading: Adult; Biological Markers; Cadmium Chloride|TO; Cells, Cultured; Dose-Response Relationship, Drug; Female; Human; Male; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0098-4108
Country of Publication: UNITED STATES

Record 13 from database: MEDLINE
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Title: Involvement of metallothionein and copper in cell proliferation.
Author: W…ostowski T
Address: Institute of Biology, Warsaw University, Bia…ystok, Poland.
Source: Biometals, 1993 Summer, 6:2, 71-6
Abstract: Metallothionein is a low-molecular weight, cysteine-rich, metal-binding protein which has been implicated in the detoxification of toxic metals (cadmium, mercury), metabolism of zinc and copper, as well as in the scavenging of free radicals. Recent evidence suggests that the protein may also be involved in cell proliferation. Based on the experiments carried out so far, it is assumed that the fundamental role of metallothionein in cell proliferation may be to detoxify and/or transfer copper ions from the cytoplasm to the nucleus at the G1/S phase, which in turn participate in some way in nuclear DNA synthesis.
Language of Publication: English
Unique Identifier: 93364161

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MeSH Heading (Major): Cell Division|*; Copper|*ME; Metallothionein|*ME
MeSH Heading: Amino Acid Sequence; Animal; Cell Cycle; Conserved Sequence; Evolution; Human

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
ISSN: 0966-0844
Country of Publication: ENGLAND
CAS Registry/EC Number: 7440-50-8 (Copper); 9038-94-2 (Metallothionein)

Record 14 from database: MEDLINE
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Title: Analysis of mammalian metallothionein isoforms by high-resolution SDS-gel electrophoresis.
Author: Koizumi S; Otaki N; Saegusa J; Otsuka F
Address: Department of Experimental Toxicology, National Institute of Industrial Health, Kawasaki, Japan.
Source: Toxicol Lett, 1993 Feb, 66:2, 165-74
Abstract: Metallothioneins (MTs) are cysteine-rich heavy metal-binding proteins, whose possible functions are thought to be the protection against toxic metals as well as the regulation of essential metals. It is known that there are several MT isoforms, but the biological roles of the individual isoforms have not been elucidated. To facilitate the functional analysis of these isoforms, we improved an analytical method of MTs developed previously, which is based on a denaturing gel electrophoresis of chemically modified MTs. The established technique makes it possible not only to separate MT isoforms with a high resolution, but to estimate the levels of the individual isoforms by analyzing directly crude cell extracts. By this method, six MT isoforms were identified in the extracts of Cd-exposed human cells. It was also revealed that there is an apparent heterogeneity of the rat liver MT; five isoforms were identified in the liver extracts of Cd-injected rats. The present method will be useful in the functional analysis of the MT isoforms, as well as in a variety of aspects of the MT studies.
Language of Publication: English
Unique Identifier: 93158027

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MeSH Heading (Major): Metallothionein|*AN/CH/IP
MeSH Heading: Animal; Electrophoresis, Polyacrylamide Gel; Hela Cells; Human; Liver|CH; Male; Mice; Rats; Rats, Inbred Lew

Publication Type: JOURNAL ARTICLE
ISSN: 0378-4274
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 9038-94-2 (Metallothionein)

Record 15 from database: MEDLINE
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Title: Regulation of metallothionein production in HeLa cells.
Author: Koizumi S; Sone T
Address: Department of Experimental Toxicology, National Institute of Industrial Health, Kawasaki, Japan.
Source: Toxicol Lett, 1991 Dec, 59:1-3, 73-80
Abstract: Metallothioneins are cysteine-rich, heavy-metal-binding proteins which have been assumed to participate in the detoxification of toxic metals. The mechanism of thionein (apoprotein of metallothionein) induction by cadmium was studied using cultured human cells. It was found that when thionein synthesis reaches a maximum (6-8 h after induction), it no longer responds to additional cadmium. Changes in cadmium uptake or induction of inhibitory proteins were not responsible. Together with our previous findings, a possible mechanism is proposed: loss of the secondary induction response might be due to increased intracellular levels of thionein, which has been overproduced by the initial induction.
Language of Publication: English
Unique Identifier: 92094614

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MeSH Heading (Major): Cadmium|ME/*TO; Metallothionein|*BI
MeSH Heading: Cells, Cultured; Cycloheximide|PD; Hela Cells|DE/ME; Human

Publication Type: JOURNAL ARTICLE
ISSN: 0378-4274
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 66-81-9 (Cycloheximide); 7440-43-9 (Cadmium); 9038-94-2 (Metallothionein)

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(Not limited to "toxic metal"

Record A1 from database: MEDLINE
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Title: Factor IX Zutphen: a Cys18-->Arg mutation results in formation of a heterodimer with alpha 1-microglobulin and the inability to form a calcium-induced conformation.
Author: Wojcik EG; van den Berg M; van der Linden IK; Poort SR; Cupers R; Bertina RM
Address: Haemostasis and Thrombosis Research Centre, University Hospital, Leiden, The Netherlands.
Source: Biochem J, 1995 Nov, 311 ( Pt 3):, 753-9
Abstract: Factor IX Zutphen is a variant factor IX molecule isolated from the blood of a patient with severe haemophilia B. The molecular defect in factor IX Zutphen is a Cys18-->Arg mutation as a result of a T-->C transition at residue 6427 of the factor IX gene of the patient. The mutation disrupts the disulphide bond in the Gla-domain between Cys18 and Cys23. The remaining free cysteine residue results in the formation of a 95 kDa complex with alpha 1-microglobulin through an intermolecular disulphide bond. The same complex circulates at high levels in plasma of carriers of the mutation. The variant molecule has a calcium-binding defect, which is shown not to be caused by incomplete gamma-carboxylation. Factor IX Zutphen can not bind to phospholipids and can not be activated by factor XIa or by factor VIIa-tissue factor complex. Two sequential metal ion-dependent conformational transitions (factor IX-->factor IX'-->factor IX*) have been proposed for human factor IX [Liebman (1987) J. Biol. Chem. 262, 7605-7612], based upon the metal ion requirements for binding to anti-factor IX:Mg(II) antibodies, which are specific for the factor IX' conformation, and anti-factor IX:Ca(II) antibodies, which are specific for the factor IX* conformation. We used these conformation-specific antibodies, and antibodies raised against a synthetic peptide corresponding to residues 35-50 of human factor IX [anti-factor IX(35-50)] to study the metal ion-induced conformation of factor IX Zutphen. The disruption of the disulphide bond in the Gla-domain, maybe in combination with the complex with alpha 1-microglobulin, destabilized the factor IX' conformation. The formation of the factor IX* conformation was prevented independent of the presence of alpha 1-microglobulin. The disulphide bond in the Gla-domain is therefore essential for the calcium-dependent conformation and function of factor IX.
Language of Publication: English
Unique Identifier: 96067589

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MeSH Heading (Major): Alpha-Globulins|*ME; Calcium|*PD; Factor IX|CH/*GE/*ME; Mutation|*
MeSH Heading: Amino Acid Sequence; Antibody Specificity; Arginine|GE/ME; Cysteine|GE/ME; Human; Metals|PD; Molecular Sequence Data; Protein Binding; Protein Conformation; Structure-Activity Relationship; Support, Non-U.S. Gov't; 1-Carboxyglutamic Acid|AN

Publication Type: JOURNAL ARTICLE
ISSN: 0264-6021
Country of Publication: ENGLAND

Record A2 from database: MEDLINE
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Title: Thiol groups and reduced acidogenicity of dental plaque in the presence of metal ions in vivo.
Author: Oppermann RV; R‡lla G; Johansen JR; Assev S
Address
Source: Scand J Dent Res, 1980 Oct, 88:5, 389-96
Abstract: Metal ions are known to influence the cariogenicity of dental plaque. Inhibition of acid metabolism in plaque may be of importance in this respect. Metal ions inhibit the acidogenicity of dental plaque to a different extent and it has been suggested that an enzyme inhibition based on oxidation of thiol groups may explain this observation. The aim of the present study was to evaluate the significance of oxidation of thiol groups in the inhibition of acid production in plaque by silver, tin and zinc salts. Nine subjects with 3-d sucrose induced plaque received topical applications of the metal ions. Cysteine or glutathione, which are known to reverse thiol oxidations, were then applied in one side of the mouth. Plaque pH measurements, in the presence of sucrose, were performed prior to and up to 2 h after treatment. The results showed that the acid production inhibited by the metal ions was reactivated by cysteine or glutathione. Iodoacetamide and p-chloromercuribenzoate were also shown to inhibit acid formation in dental plaque. The high affinity silver, tin and zinc have for SH groups, the observed inhibitory effect of these metals, the reactivation of the metabolism by monothiols and the fact that organic sulfhydryl reagents inhibit acid formation in plaque indicate that oxidation of thiol groups may be the mechanism by which these metals exert their effect.
Language of Publication: English
Unique Identifier: 81126114

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MeSH Heading (Major): Cariogenic Agents|*; Dental Plaque|*ME; Metals|*PD; Sulfhydryl Compounds|*ME
MeSH Heading: Adult; Cysteine|PD; Glutathione|ME; Human; Hydrogen-Ion Concentration; Oxidation-Reduction; Silver|PD; Streptococcus mutans|GD; Tin|PD; Zinc|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0029-845X
Country of Publication: DENMARK
CAS Registry/EC Number: 0 (Cariogenic Agents); 0 (Metals); 0 (Sulfhydryl Compounds); 4371-52-2 (Cysteine); 70-18-8 (Glutathione); 7440-22-4 (Silver); 7440-31-5 (Tin); 7440-66-6 (Zinc)

Record A3 from database: MEDLINE
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Title: Antibody constant region: potential to bind metal and nucleic acid.
Author: Radulescu RT
Address: Molecular Concepts Research (MCR), Munich, Germany.
Source: Med Hypotheses, 1995 Feb, 44:2, 139-45
Abstract: Environmental challenges appear to elicit similar patterns of cellular responses such as positive autoregulation and autoamplification whether one considers the generation of antibodies with identical antigen specificity or the accumulation of host-protective transcription factors. Therefore, I analyzed the structure of immunoglobulins (Ig) for motifs commonly found in transcription factors. Specifically, the well-known abundance and periodic location of cysteine residues in immunoglobulin chains prompted me to check antibody constant regions for the presence of putative metal-binding domains and zinc finger-like sequences. The constant regions of Ig light and heavy chains were found to harbor one or several copies, respectively, of a short cysteine- and histidine-containing sequence. Moreover, all four IgG subclasses were detected to comprise zinc finger-like motifs in their heavy chain constant and hinge domains. Yet another finding is the occurrence of several sequences of the form serine-proline-X-X and/or threonine-proline-X-X in the hinge sections of IgA and IgG3. These results suggest that antibody constant regions, as a fragment and/or embedded in a full-length immunoglobulin chain, may complex metal, thus acquiring conformations conducive to dimerization and nucleic acid binding. As such, my study provides a putative structural basis for the known requirement of divalent metal cations, particularly of zinc ions, for a normal immune response, and warrants further investigations, both theoretical and experimental, into the potential of antibody constant regions for metal binding and gene regulation. Moreover, future testing of the proposed zinc finger peptides from Ig constant domains should yield information relevant to zinc finger design with potentially wide applications in research and clinical medicine.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication: English
Unique Identifier: 95319353

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MeSH Heading (Major): DNA-Binding Proteins|*ME; Immunoglobulin Constant Region|CH/*ME; Metals|*ME; Models, Genetic|*; Models, Immunological|*; Zinc Fingers|*
MeSH Heading: Amino Acid Sequence; Cysteine; Evolution; Gene Expression Regulation; Human; Molecular Sequence Data; RNA, Viral|ME; Sequence Alignment; Signal Transduction; Transcription Factors|CH; Zinc|ME

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
ISSN: 0306-9877
Country of Publication: ENGLAND

Record A4 from database: MEDLINE
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Title: Dimerization of the human papillomavirus E7 oncoprotein in vivo.
Author: Clemens KE; Brent R; Gyuris J; Münger K
Address: Laboratory of Molecular Virology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Source: Virology, 1995 Dec, 214:1, 289-93
Abstract: We have used a yeast two-hybrid system to show that human papillomavirus E7 proteins can form oligomeric complexes in vivo. The carboxyl-terminal cysteine-rich metal-binding domain is critical for this activity although amino-terminal sequences also contribute to oligomerization. Our experiments also reveal that E7 possesses an intrinsic transcription activation activity in yeast, which resides in the amino terminus of the protein.
Language of Publication: English
Unique Identifier: 96095252

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MeSH Heading (Major): Oncogene Proteins, Viral|*ME
MeSH Heading: Amino Acid Sequence; Binding Sites; Biopolymers; Cysteine|ME; Human; Metals|ME; Molecular Sequence Data; Structure-Activity Relationship; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Trans-Activation (Genetics); Yeasts

Publication Type: JOURNAL ARTICLE
ISSN: 0042-6822
Country of Publication: UNITED STATES

Record A5 from database: MEDLINE
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Title: Cysteine metabolism and metal toxicity.
Author: Quig D
Address: Doctor's Data, Inc., West Chicago, IL, USA. dquig@doctorsdata.com
Source: Altern Med Rev, 1998 Aug, 3:4, 262-70
Abstract: Chronic, low level exposure to toxic metals is an increasing global problem. The symptoms associated with the slow accumulation of toxic metals are multiple and rather nondescript, and overt expression of toxic effects may not appear until later in life. The sulfhydryl-reactive metals (mercury, cadmium, lead, arsenic) are particularly insidious and can affect a vast array of biochemical and nutritional processes. The primary mechanisms by which the sulfhydryl-reactive metals elicit their toxic effects are summarized. The pro-oxidative effects of the metals are compounded by the fact that the metals also inhibit antioxidative enzymes and deplete intracellular glutathione. The metals also have the potential to disrupt the metabolism and biological activities of many proteins due to their high affinity for free sulfhydryl groups. Cysteine has a pivotal role in inducible, endogenous detoxication mechanisms in the body, and metal exposure taxes cysteine status. The protective effects of glutathione and the metallothioneins are discussed in detail. Basic research pertaining to the transport of toxic metals into the brain is summarized, and a case is made for the use of hydrolyzed whey protein to support metal detoxification and neurological function. Metal exposure also affects essential element status, which can further decrease antioxidation and detoxification processes. Early detection and treatment of metal burden is important for successful detoxification, and optimization of nutritional status is paramount to the prevention and treatment of metal toxicity.
Language of Publication: English
Unique Identifier: 98404750

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MeSH Heading (Major): Arsenic|ME/*PO; Cysteine|DE/*ME; Metals, Heavy|ME/*PO
MeSH Heading: Chronic Disease; Endocrine Glands|DE; Human; Leucine|ME; Mercury|ME; Mercury Poisoning|ME/TH; Oxidation-Reduction|DE; Poisoning|TH

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL
ISSN: 1089-5159
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals, Heavy); 4371-52-2 (Cysteine); 7005-03-0 (Leucine); 7439-97-6 (Mercury); 7440-38-2 (Arsenic)

Record A6 from database: MEDLINE
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Title: NMR analysis of the structure and metal sequestering properties of metallothioneins.
Author: Armitage IM; Dalgarno DC; Johnson BA
Address: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510.
Source: EXS, 1987, 52:, 159-69
Abstract: Multinuclear 1 and 2 dimensional magnetic resonance methods have been used to investigate the structures and metal binding properties of metallothioneins (MTs) isolated from several different sources. 113Cd NMR studies have unambiguously shown that the 7 g-atoms of Cd2+ bound per mole of the mammalian MT are located in two separate metal clusters, one containing 4 metal ions and the other, 3 metal ions. In the invertebrate (Scylla serrata) MT, similar studies have revealed that the 6 g-atoms of bound Cd2+ are distributed in two distinct 3-metal clusters while in Neurospora MT, the 3 g-atoms of bound Cd2+ are arranged in a pseudo 3-metal cluster. With the exception of one of the Cd2+ sites in this latter cluster, all the Cd2+ ions are tetrahedrally coordinated to four cysteine thiolate ligands with single cysteinyl sulfurs bridging adjacent metals. These conclusions are based on the 113Cd chemical shift data and a detailed analysis of the observed 113Cd-113Cd scalar couplings by both homonuclear decoupling and 2D techniques. In addition, the 113Cd NMR studies have revealed significant differences in the affinity of different metal ions for the two mammalian metal clusters. For the 3-metal cluster, the affinity is found to decrease in the order Cu+ greater than Cd2+ greater than Zn2+ with Cd2+ greater than Zn2+ for the 4 metal cluster and Cd2+ (4-metal cluster) greater than Cd2+ (3-metal cluster). The 113Cd NMR data are currently being integrated with 500 MHz 2D 1H and 1H-113Cd chemical shift correlated multiple quantum data sets to more completely define the structural arrangement of the metal clusters in the tertiary structure of these proteins.
Language of Publication: English
Unique Identifier: 88029878

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MeSH Heading (Major): Metallothionein|*ME; Metals|*ME
MeSH Heading: Amino Acid Sequence; Animal; Cadmium|ME; Comparative Study; Copper|ME; Crabs; Cysteine; Human; Liver|AN; Molecular Sequence Data; Neurospora crassa|AN; Nuclear Magnetic Resonance; Protein Conformation; Rabbits; Saccharomyces cerevisiae|AN; Support, U.S. Gov't, P.H.S.; Zinc|ME

Publication Type: JOURNAL ARTICLE
Country of Publication: SWITZERLAND
CAS Registry/EC Number: 0 (Metals); 4371-52-2 (Cysteine); 7440-43-9 (Cadmium); 7440-50-8 (Copper); 7440-66-6 (Zinc); 9038-94-2 (Metallothionein)

Record A7 from database: MEDLINE
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Title: Copper ions differ from other thiol reactive metal ions in their effects on the concentration and redox status of thiols in HeLa cell cultures.
Author: Hultberg B; Andersson A; Isaksson A
Address: Department of Clinical Chemistry, University Hospital, Lund, Sweden.
Source: Toxicology, 1997 Feb, 117:2-3, 89-97
Abstract: Ions of metals such as copper, mercury, silver and cadmium are known to exhibit a high affinity for thiol groups and may therefore severely disturb many metabolic functions in the cell. Copper ions are also known to catalyse the formation of toxic oxygen species through a series of redox reactions. In the present study, we have determined the concentration of reduced and total glutathione, cysteine and homocysteine in a cell culture system (HeLa cell line) after addition of these metal ions. The main findings of the metal ion effect on the total thiol concentrations are that all metal ions increased the release of glutathione into the medium. Since the intracellular concentration of glutathione did not decrease under these conditions, the synthesis of glutathione must have been increased. In contrast to the other metal ions, copper ions also increased the release of homocysteine into the medium, possibly through interaction with S-adenosylhomocysteine hydrolase. The main findings of metal ion effects on reduced thiol are that, at concentrations not interfering with cell growth, mercury, silver and cadmium ions increased the concentration of extracellular reduced glutathione, possibly reflecting the increase of total glutathione in the medium. In contrast to the other metal ions, the addition of even very low amounts of copper ions (1 mumol/l) decreased the concentration of intra- and extracellular reduced thiols indicating oxidative stress.
Language of Publication: English
Unique Identifier: 97210824

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MeSH Heading (Major): Copper|*TO; Cysteine|*DE/ME; Glutathione|BI/*DE; Hela Cells|*DE/ME; Homocysteine|*DE/ME; Metals, Heavy|*TO
MeSH Heading: Animal; Cadmium|TO; Cations|TO; Human; Mercury|TO; Oxidation-Reduction; Oxidative Stress|DE; Silver|TO; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0300-483X
Country of Publication: IRELAND

Record A8 from database: MEDLINE
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Title: Affinity cleavage at the metal-binding site of phosphoenolpyruvate carboxykinase.
Author: Hlavaty JJ; Nowak T
Address: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Source: Biochemistry, 1997 Dec, 36:49, 15514-25
Abstract: Chicken liver phosphoenolpyruvate carboxykinase (PEPCK) was rapidly inactivated by micromolar concentrations of ferrous sulfate in the presence of ascorbate at pH 7.4. Omitting ascorbate or replacing the Fe2+ with Mn2+ or Mg2+ gives no inactivation. Mn2+, Mg2+, or Co2+ at 100-fold molar excess over Fe2+ offered complete protection from Fe2+/ascorbate-induced inactivation. The substrates PEP and GTP, but not OAA, GDP, or CO2, offered full protection from inactivation. The addition of 5 mM EDTA stopped further inactivation of the enzyme. Thermodynamic studies indicate that the inactive enzyme no longer binds Mn2+ but still had high affinity for GTP indicating that the inactivation process was specific for the metal site. A decrease in cysteine content was observed over time following PEPCK treatment with Fe2+ and ascorbate. The apparent first-order rate constant for free sulfhydryl loss (0.085 +/- 0.005 min-1) is similar to the apparent first-order rate constant for inactivation (0.067 +/- 0.005 min-1). Amino acid composition analysis revealed that cysteic acid was generated upon Fe2+/ascorbate addition to PEPCK. Native chicken liver PEPCK has an Mr of 67 kDa. SDS-PAGE of the inactivated enzyme showed the presence of two new bands at 31.7 and 35.3 kDa indicating that PEPCK was specifically cleaved at a single site. The rate of cleavage was slower than the rate of inactivation and fully inactivated enzyme was only 50% cleaved. The Fe2+/ascorbate-catalyzed inactivation was not solely due to protein cleavage. The protein fragments generated by cleavage were separated by C4 reverse phase HPLC. The cleavage exposed a new N-terminus which was identified to be the 35.3 kDa C-terminal half of PEPCK. Sequencing of the fragments indicated that the site of cleavage was between Asp296 and Ile297. These results indicate that Asp296 is involved in metal chelation. This agrees with previous studies [Hlavaty, J. J., & Nowak, T. (1997) Biochemistry 36, 3389-3403] that suggested that Asp295 and Asp296 are involved in metal binding.
Language of Publication: English
Unique Identifier: 98060805

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MeSH Heading (Major): Metals|*ME; Phosphoenolpyruvate Carboxykinase (GTP)|AI/IP/*ME
MeSH Heading: Amino Acid Sequence; Animal; Ascorbic Acid|PD; Binding Sites; Chickens; Chromatography, High Pressure Liquid; Cysteine|CH; Free Radical Scavengers; Guanosine Triphosphate|ME; Human; Hydrolysis; Kinetics; Liver|EN; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Tryptophan|CH

Publication Type: JOURNAL ARTICLE
ISSN: 0006-2960
Country of Publication: UNITED STATES

Record A9 from database: MEDLINE
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Title: Solution structure of the fourth metal-binding domain from the Menkes copper-transporting ATPase [see comments]
Author: Gitschier J; Moffat B; Reilly D; Wood WI; Fairbrother WJ
Address: Howard Hughes Medical Institute, University of California, San Francisco 94143, USA.
Source: Nat Struct Biol, 1998 Jan, 5:1, 47-54
Abstract: Menkes disease is an X-linked disorder in copper transport that results in death during early childhood. The solution structures of both apo and Ag(I)-bound forms of the fourth metal-binding domain (mbd4) from the Menkes copper-transporting ATPase have been solved. The 72-residue mbd4 has a ferredoxin-like beta alpha beta beta alpha beta fold. Structural differences between the two forms are limited to the metal-binding loop, which is disordered in the apo structure but well ordered in the Ag(I)-bound structure. Ag(I) binds in a linear bicoordinate manner to the two Cys residues of the conserved GMTCxxC motif; Cu(I) likely coordinates in a similar manner. Menkes mbd4 is thus the first bicoordinate copper-binding protein to be characterized structurally. Sequence comparisons with other heavy-metal-binding domains reveal a conserved hydrophobic core and metal-binding motif.
Language of Publication: English
Unique Identifier: 98100082

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MeSH Heading (Major): Adenosinetriphosphatase|CH/*UL; Carrier Proteins|CH/*UL; Copper|*
MeSH Heading: Amino Acid Sequence; Apoproteins|CH/UL; Binding Sites; Cysteine|CH; Human; Membrane Proteins|UL; Metals, Heavy; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Protein Structure, Secondary; Protein Structure, Tertiary; Recombinant Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Solutions; Structure-Activity Relationship; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 1072-8368
Country of Publication: UNITED STATES

Record A10 from database: MEDLINE
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Title: Role of sulfhydryls in the hepatotoxicity of organic and metallic compounds.
Author: Klaassen CD; Bracken WM; Dudley RE; Goering PL; Hazelton GA; Hjelle JJ
Address
Source: Fundam Appl Toxicol, 1985 Oct, 5:5, 806-15
Abstract: Endogenous sulfhydryl compounds serve a critical role in maintaining the function and viability of living systems. Glutathione (GSH) is the most abundant of these nonprotein thiols. During the past decade it has been demonstrated that sulfhydryls such as GSH also serve an important role in protecting vital nucleophilic sites in the liver from electrophilic attack by numerous classes of reactive chemicals. Organocompounds such as bromobenzene and acetaminophen which undergo microsomal metabolism yield reactive intermediates that are specifically inactivated by conjugation with sulfhydryls in the form of GSH. Thus, for organocompounds GSH is extremely important in protecting against toxic insults. More recently, other sulfhydryl compounds also have been found to serve a specific but as yet less defined role in protecting biological systems against chemically induced injury. Metals such as cadmium have a high affinity for sulfhydryls and the metal binding protein metallothionein binds cadmium with high affinity. The highly specific association of the metal with this sulfhydryl-enriched protein serves to effectively sequester the reactive cadmium ion. The central role of sulfhydryl equivalents in the detoxication of organo- and metallocompounds is similar; however, the mechanism by which this is achieved is fundamentally different.
Language of Publication: English
Unique Identifier: 86056693

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MeSH Heading (Major): Hepatitis, Toxic|*ME; Metals|*TO; Sulfhydryl Compounds|*ME
MeSH Heading: Acetaminophen|TO; Animal; Biotransformation; Bromobenzenes|TO; Cadmium Poisoning|ME; Cysteine|PD; Cytochrome P-450|ME; Human; Metallothionein|ME; Microsomes, Liver|EN; Support, U.S. Gov't, P.H.S.; Zinc|TO

Publication Type: JOURNAL ARTICLE
ISSN: 0272-0590
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Bromobenzenes); 0 (Metals); 0 (Sulfhydryl Compounds); 103-90-2 (Acetaminophen); 4371-52-2 (Cysteine); 7440-66-6 (Zinc); 9035-51-2 (Cytochrome P-450); 9038-94-2 (Metallothionein)

Record A11 from database: MEDLINE
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Title: Selective inactivation of butyrylcholinesterase with metal chelators suggests there is more than one metal binding site.
Author: Bhanumathy CD; Balasubramanian AS
Address: Department of Neurological Sciences, Christian Medical College and Hospital, Tamil Nadu, India.
Source: Int J Biochem Cell Biol, 1998 Jun, 30:6, 695-705
Abstract: Cholinesterases exhibit functions apart from their esterase activity. We have demonstrated an aryl acylamidase and a zinc stimulated metallocarboxypeptidase activity in human serum butyrylcholinesterase. To establish the presence of zinc binding sites in the enzyme we examined the effect of metal chelators on its catalytic activities. The metal chelators 1,10-phenanthroline and N,N,N',N'-tetrakis (2-pyridyl methyl)ethylene diamine (TPEN) inhibited all the three catalytic activities in the enzyme. However, EDTA inhibited the peptidase activity exclusively without affecting the cholinesterase and aryl acylamidase activities. The catalytic activities were recovered upon removal of the chelator by Sephadex G-25 chromatography. Pre-treatment of the enzyme with any one of the three chelators resulted in the binding of the enzyme to a zinc-Sepharose column or to 65Zn2+. Histidine modification of the enzyme pretreated with chelators resulted in abolition of 65Zn2+ binding and zinc-Sepharose binding. Whereas the binding studies demonstrated removal of a metal from a Zn2+ binding site, attempts to remove the metal responsible for catalytic activity were unsuccessful. Atomic absorption spectroscopy indicated approximately 2.5 mol of zinc per mol of enzyme before treatment with EDTA and 1 mol zinc per mol enzyme after EDTA treatment. The results indicate that there are at least two metal binding sites on butyrycholinesterase. The presence of two HXXE...H sequences in butyrylcholinesterase supports these findings. Our studies implicate a zinc dependent metallocarboxypeptidase activity in the non-cholinergic functions of butyrylcholinesterase.
Language of Publication: English
Unique Identifier: 98360139

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MeSH Heading (Major): Butyrylcholinesterase|*ME; Chelating Agents|*PD; Cholinesterase Inhibitors|*PD; Ethylenediamines|*PD; Phenanthrolines|*PD
MeSH Heading: Binding Sites; Catalysis; Chromatography, Gel; Cysteine; Dextrans; Edetic Acid|PD; Histidine; Human; Metals; Spectrophotometry, Atomic Absorption; Support, Non-U.S. Gov't; Time Factors; Zinc

Publication Type: JOURNAL ARTICLE
ISSN: 1357-2725
Country of Publication: ENGLAND
CAS Registry/EC Number: EC 3.1.1.- (Butyrylcholinesterase); 0 (Chelating Agents); 0 (Cholinesterase Inhibitors); 0 (Ethylenediamines); 0 (Metals); 0 (Phenanthrolines); 16858-02-9 (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine); 4371-52-2 (Cysteine); 60-00-4 (Edetic Acid); 66-71-7 (1,10-phenanthroline); 7006-35-1 (Histidine); 7440-66-6 (Zinc); 9004-54-0 (Dextrans); 9014-76-0 (sephadex)

Record A12 from database: MEDLINE
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Title: Reversal of heavy metal resistance in multidrug-resistant human KB carcinoma cells.
Author: Chen ZS; Mutoh M; Sumizawa T; Furukawa T; Haraguchi M; Tani A; Akiyama S
Address: Department of Cancer Chemotherapy, Institute for Cancer Research, Faculty of Medicine, Kagoshima University, Japan.
Source: Biochem Biophys Res Commun, 1997 Jul, 236:3, 586-90
Abstract: Human KB carcinoma C-A120 cells that express multidrug resistance-associated protein (MRP) were cross-resistant to trivalent and pentavalent antimonials and arsenicals. Intracellular glutathione (GSH) content was higher in C-A120 than its parental KB-3-1 cell line. Glutathione-S-transferase (GST) was similar in both cell lines. Depletion of cellular GSH by treatment of the cells with the inhibitor of gamma-glutamylcysteine synthetase (gamma-GCS), buthione sulfoximine (BSO), significantly increased the sensitivity of both KB-3-1 and C-A120 cells to heavy metals. A pyridine analog, PAK-104P, almost completely reversed the resistance to antimonials and arsenicals in C-A120 cells. BSO at 100 microM or PAK-104P at 10 microM enhanced the accumulation of antimony potassium tartrate in C-A120 cells to the level of that in KB-3-1 cells without the agents. PAK-104P inhibited the ATP-dependent efflux of antimony potassium tartrate. These findings suggest that MRP transports antimony conjugated with GSH ATP-dependently outside the cells and PAK-104P inhibits the transporting activity of MRP.
Language of Publication: English
Unique Identifier: 97396139

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MeSH Heading (Major): ABC Transporters|*ME; Drug Resistance, Multiple|*; Drug Resistance, Neoplasm|*; Metals, Heavy|*PD
MeSH Heading: Adenosine Triphosphate|PD; Antimony|ME/PD; Antimony Potassium Tartrate|ME; Arsenic|PD; Buthionine Sulfoximine|PD; Cyclic P-Oxides|PD; Enzyme Inhibitors|PD; Glutamate-Cysteine Ligase|AI; Glutathione|ME; Glutathione Transferase|ME; Human; KB Cells; Nicotinic Acids|PD; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES

Record A13 from database: MEDLINE
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Title: Patients with homocystinuria: high metal concentrations in hair, blood and urine.
Author: Yoshida Y; Nakano A; Hamada R; Kamitsuchibashi H; Yamamoto K; Akagi H; Kitazono M; Osame M
Address: School of Allied Medical Science, Kagoshima University, Japan.
Source: Acta Neurol Scand, 1992 Nov, 86:5, 490-5
Abstract: Patients with homocystinuria excrete a large amount of metal in their urine. Homocysteine similar to penicillamine, administration to methylmercury treated rats resulted in a large amount of urinary methylmercury excretion. These results suggested that the total metal amounts in the whole body of patients with homocystinuria might be decreased. However, actually metal concentrations in hair and plasma of these patients were higher than those of normal controls. High plasma and hair metal levels are not accounted for in patients with homocystinuria. The physiological metal excretory mechanism in which small amounts of metals bind to the small, plasma molecular substances filter through the kidney and emerge in the urine is necessary for reconfirmation. Strongly perturbed metal metabolism exists in the patients with homocystinuria.
Language of Publication: English
Unique Identifier: 93127798

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MeSH Heading (Major): Hair|*ME; Homocystinuria|DH/*UR; Metals|*PK
MeSH Heading: Adult; Animal; Brain|ME; Case Report; Cysteine|AD/PK; Female; Homocysteine|AD/PK; Human; Male; Methylmercury Compounds|PK; Rats; Rats, Wistar; Reference Values; Tissue Distribution

Publication Type: JOURNAL ARTICLE
ISSN: 0001-6314
Country of Publication: DENMARK
CAS Registry/EC Number: 0 (Metals); 0 (Methylmercury Compounds); 4371-52-2 (Cysteine); 454-28-4 (Homocysteine)

Record A14 from database: MEDLINE
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Title: Purification of glycogen phosphorylase isozymes by metal-affinity chromatography.
Author: Luong CB; Browner MF; Fletterick RJ; Haymore BL
Address: Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.
Source: J Chromatogr, 1992 Dec 11, 584:1, 77-84
Abstract: Mammalian phosphorylase isozymes from muscle, brain and liver were expressed in Escherichia coli and purified from the crude bacterial cell extracts in one step using a copper-loaded, metal-affinity matrix. Good chromatographic behavior, enzyme activity and protein stability were maintained by judicious choice of pH and buffer which contained 250 mM sodium chloride and 25 mM beta-glycerophosphate at pH 7.0. Small amounts of beta-mercaptoethanol and EDTA in the buffers further stabilized the enzymes, but stripped some of the metal from the column which, nonetheless, retained good chromatographic characteristics. Owing to the presence of multiple surface histidine residues in the phosphorylase dimers, good enzyme purities (90-98%) and recoveries (>90%) were routinely obtained from crude bacterial lysates after two passes through the copper column. Of the various metal ions which were investigated, Cu2+ gave the best chromatographic results. Imidazole gradients at constant pH were used to selectively desorb the phosphorylase from the metal column whose capacity for phosphorylase binding in the presence of bacterial proteins exceeded 30 mg enzyme per milliliter of matrix.
Language of Publication: English
Unique Identifier: 93139178

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MeSH Heading (Major): Chromatography, Affinity|*MT; Glycogen Phosphorylase|*IP; Isoenzymes|*IP
MeSH Heading: Animal; Chromatography, Ion Exchange; Cysteine|AN; Electrophoresis, Polyacrylamide Gel; Human; Hydrogen-Ion Concentration; Imino Acids; Metals; Rabbits; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9673
Country of Publication: NETHERLANDS
CAS Registry/EC Number: EC 2.4.1.1 (Glycogen Phosphorylase); 0 (Imino Acids); 0 (Isoenzymes); 0 (Metals); 14219-31-9 (copper(II)-iminodiacetate); 4371-52-2 (Cysteine)

Record A15 from database: MEDLINE
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Title: A structural role for metal ions in the "wild-type" conformation of the tumor suppressor protein p53.
Author: Hainaut P; Milner J
Address: Department of Biology, University of York, Heslington, United Kingdom.
Source: Cancer Res, 1993 Apr 15, 53:8, 1739-42
Abstract: In human tumors, many different point mutations of the p53 gene knock out suppressor function and induce the p53 polypeptide to adopt an immunologically distinct, "mutant" conformation. Here we show that exposure to the metal chelator 1,10-phenanthroline induces wild-type p53 to adopt the mutant conformation and that this process is reversible. Conversion to mutant phenotype also occurs after exposure to (a) an organic mercurial reagent targeting cysteinyl residues and (b) low concentrations of mercury or cadmium. We propose that binding of metal ions, most probably zinc, to conserved cysteinyl residues stabilizes the tertiary structure of wild-type p53.
Language of Publication: English
Unique Identifier: 93223179

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MeSH Heading (Major): Metals|*PD; Protein p53|*CH
MeSH Heading: Amino Acid Sequence; Animal; Cysteine|CH; Edetic Acid|PD; Egtazic Acid|PD; Human; Mice; Molecular Sequence Data; Protein Conformation|DE; Rabbits; Support, Non-U.S. Gov't; Zinc|ME/PD

Publication Type: JOURNAL ARTICLE
ISSN: 0008-5472
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals); 0 (Protein p53); 4371-52-2 (Cysteine); 60-00-4 (Edetic Acid); 67-42-5 (Egtazic Acid); 7440-66-6 (Zinc)

Record A16 from database: MEDLINE
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Title: Immobilized metal ion affinity chromatography of serum albumins.
Author: Andersson L; Sulkowski E; Porath J
Address: Institute of Biochemistry and Biochemical Separation Center, Uppsala University, Sweden.
Source: Bioseparation, 1991, 2:1, 15-22
Abstract: The interaction of several serum albumins with chelated (iminodiacetate, IDA) and immobilized (agarose-IDA) metal ions, Co2+, Ni2+, Cu2+ and Zn2+, was studied. There was no retention of human, bovine, porcine, murine and avian albumins on IDA-Zn(II) and IDA-Co(II) columns. However, all albumins studied, i.e., those of: man, cow, pig, dog, rabbit, rat, mouse, chicken and pigeon were retained on IDA-Cu(II) columns, and all except dog albumin were retained also on IDA-Ni(II). The recognition of albumins by chelated and immobilized transition metals seems to be related to an affinity for the imidazole side chains. It is postulated that one to three imidazoles is involved in this interaction, under the employed experimental conditions (pH 7.0; 1 M sodium chloride). There is no evidence for any significant contribution of tryptophan or cysteine (Cys 34) residues to the chromatographic event. The retention of defatted albumin and albumin oligomers (human), on IDA-Cu(II) columns was not significantly different from that of non-defatted albumin or albumin monomer, respectively.
Language of Publication: English
Unique Identifier: 92240092

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MeSH Heading (Major): Serum Albumin|*IP
MeSH Heading: Animal; Chromatography, Affinity; Cysteine; Dogs; Histidine; Human; Metals; Serum Albumin, Bovine|IP; Support, Non-U.S. Gov't; Tryptophan

Publication Type: JOURNAL ARTICLE
ISSN: 0923-179X
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 0 (Metals); 0 (Serum Albumin); 0 (Serum Albumin, Bovine); 4371-52-2 (Cysteine); 6912-86-3 (Tryptophan); 7006-35-1 (Histidine)

Record A17 from database: MEDLINE
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Title: Metallothionein: an exceptional metal thiolate protein.
Author: Kägi JH; Kojima Y; Kissling MM; Lerch K
Address
Source: Ciba Found Symp, 1979, :72, 223-37
Abstract: Metallothioneins are unusual, low molecular weight proteins of extremely high sulphur and metabl content. They occur in substantial quantity and in multiple variant forms in parenchymatous tissues (liver, kidney, intestines) of vertebrates and certain microorganisms (Neurospora crassa, yeast). They are though to play a central role in the cellular metabolism of F; metals such as zinc, copper and cadmium. All mammalian forms studied are single chains with 20 cysteinyl residues among a total of 61 amino acid residues and highly characteristic amino acid sequences. Their most conspicuous common features are seven -Cys-X-Cys- sequences where X stands for an alphatic residue other than Cys. Together with additional cysteinyl residues located elsewhere in the chain and brought into juxtaposition by appropriate chain folding, these dithiol sequences are believed to form the basis of the trithiolate chelating structures typical of most of the six or seven metal-binding sites of the mammalian cadium- and/or zinc-containing metallothioneins. The positions of the cysteinyl residues are preserved in evolution: the copper-containing metallothionein from Neurospora crassa, containing only 25 amino acid residues, has a distribution of metal-binding cysteinyl residues identical to that of the N-terminal portion of the mammalian chains. The detailed physiological role of metallothionein remains to be clarified but its biosynthesis is known to be modulated by nutritional and endocrine factors. Recent evidence suggests that metallothionein is a critical determinant in the homeostasis of zinc.
Language of Publication: English
Unique Identifier: 80245602

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MeSH Heading (Major): Metalloproteins|*AN; Metallothionein|*AN/BI/ME/PD
MeSH Heading: Amino Acid Sequence; Animal; Cysteine|IP; Gastrointestinal System|AN; Human; Kidney|AN; Liver|AN; Neurospora crassa|ME

Publication Type: JOURNAL ARTICLE; REVIEW
ISSN: 0300-5208
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 0 (Metalloproteins); 4371-52-2 (Cysteine); 9038-94-2 (Metallothionein)

Record A18 from database: MEDLINE
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Title: Combined deficiency of xanthine oxidase and sulphite oxidase: a defect of molybdenum metabolism or transport?
Author: Duran M; Beemer FA; van de Heiden C; Korteland J; de Bree PK; Brink M; Wadman SK; Lombeck I
Address
Source: J Inherit Metab Dis, 1978, 1:4, 175-8
Abstract: A child is described who presented in the neonatal period with feeding difficulties, severe neurological abnormalities, lens dislocation of the eyes and dysmorphic symptoms of the head. Routine laboratory investigations revealed a decreased serum urate and a positive sulphite reaction of the urine. Subsequent chromatographic examinations showed xanthinuria and increased excretion of S-sulphocysteine and taurine to be present. In addition, high thiosulphate and low sulphate excretions in the urine were observed. Xanthine oxidase deficiency was demonstrated in a jejunal biopsy specimen, whereas the excretion of sulphur containing substances was considered to be characteristic of sulphite oxidase deficiency. This new combination of defects may be the result of malfunctioning of both enzymes, possibly caused by alterations in the essential molybdenum containing active centre of the enzymes, which they share in common.
Language of Publication: English
Unique Identifier: 80076214

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MeSH Heading (Major): Metal Metabolism, Inborn Errors|*ME; Molybdenum|*ME; Oxidoreductases|*DF; Sulfite Oxidases|*DF; Xanthine Oxidase|*DF
MeSH Heading: Abnormalities, Multiple|ME; Biological Transport; Case Report; Cysteine|ME; Female; Human; Infant, Newborn

Publication Type: JOURNAL ARTICLE
ISSN: 0141-8955
Country of Publication: ENGLAND

Record A19 from database: MEDLINE
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Title: An engineered cysteine in the external mouth of a K+ channel allows inactivation to be modulated by metal binding.
Author: Yellen G; Sodickson D; Chen TY; Jurman ME
Address: Department of Neurobiology, Harvard Medical School, Boston, Massachusetts.
Source: Biophys J, 1994 Apr, 66:4, 1068-75
Abstract: Substitution of a cysteine in the extracellular mouth of the pore of the Shaker-delta K+ channel permits allosteric inhibition of the channel by Zn2+ or Cd2+ ions at micromolar concentrations. Cd2+ binds weakly to the open state but drives the channel into the slow (C-type) inactivated state, which has a Kd for Cd2+ of approximately 0.2 microM. There is a 45,000-fold increase in affinity when the channel changes from open to inactivated. These results indicate that C-type inactivation involves a structural change in the external mouth of the pore. This structural change is reflected in the T449C mutant as state-dependent metal affinity, which may result either from a change in proximity of the introduced cysteine residues of the four subunits or from a change of the exposure of this residue on the surface of the protein.
Language of Publication: English
Unique Identifier: 94312628

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MeSH Heading (Major): Potassium Channels|AI/GE/*ME
MeSH Heading: Allosteric Regulation|GE; Animal; Binding Sites; Biophysics; Cadmium|ME/PD; Cell Line; Comparative Study; Cysteine|GE/ME; Human; Kinetics; Models, Biological; Mutagenesis, Site-Directed; Protein Binding; Protein Conformation; Protein Engineering; Support, U.S. Gov't, P.H.S.; Zinc|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0006-3495
Country of Publication: UNITED STATES

Record A20 from database: MEDLINE
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Title: Structure of mammalian metallothionein.
Author: Kägi JH; Vasák M; Lerch K; Gilg DE; Hunziker P; Bernhard WR; Good M
Address
Source: Environ Health Perspect, 1984 Mar, 54:, 93-103
Abstract: All mammalian metallothioneins characterized contain a single polypeptide chain of 61 amino acid residues, among them 20 cysteines providing the ligands for seven metal-binding sites. Native metallothioneins are usually heterogeneous in metal composition, with Zn, Cd, and Cu occurring in varying proportions. However, forms containing only a single metal species, i.e., Zn, Cd, Ni, Co, Hg, Pb, Bi, have now been prepared by in vitro reconstitution from the metal-free apoprotein. By spectroscopic analysis of such derivatives it was established that all cysteine residues participate in metal binding, that each metal ion is bound to four thiolate ligands, and that the symmetry of each complex is close to that of a tetrahedron. To satisfy the requirements of the overall Me7(Cys-)20 stoichiometry, the complexes must be combined to form metal-thiolate cluster structures. Experimental proof for the occurrence of such clusters comes from the demonstration of metal-metal interactions by spectroscopic and magnetic means. Thus, in Co(II)7-metallothionein, the Co(II)-specific ESR signals are effectively suppressed by antiferromagnetic coupling of juxtaposed paramagnetic metal ions. By monitoring changes in ESR signal size occurring on stepwise incorporation of Co(II) into the protein, it is possible to follow the building up of the clusters. This process is biphasic. Up to binding of four equivalents of Co(II), the ESR amplitude increases in proportion to the metal content, indicating generation of magnetically noninteracting high-spin complexes. However, upon addition of the remaining three equivalents of Co(II), these features are progressively suppressed, signaling the formation of clusters. The same mode of cluster formation has also been documented for Cd and Hg. The actual spatial organization of the clusters and the polypeptide chain remains to be established. An attractive possibility is the arrangement of the tetrahedral metal-thiolates in adamantane-like structures surrounded by properly folded segments of the chain providing the ligands. 1H-NMR data and infrared absorption measurements are consistent with a tightly folded structure rich in beta-type conformation.
Language of Publication: English
Unique Identifier: 84235931

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MeSH Heading (Major): Metallothionein|*AN
MeSH Heading: Amino Acid Sequence; Animal; Cobalt|AN; Cysteine|AN; Electron Spin Resonance Spectroscopy; Human; Nuclear Magnetic Resonance; Spectrophotometry, Infrared; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0091-6765
Country of Publication: UNITED STATES
CAS Registry/EC Number: 4371-52-2 (Cysteine); 7440-48-4 (Cobalt); 9038-94-2 (Metallothionein)

Record A21 from database: MEDLINE
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Title: NMR analysis of the structure and metal sequestering properties of metallothioneins.
Author: Hunt CT; Boulanger Y; Fesik SW; Armitage IM
Address
Source: Environ Health Perspect, 1984 Mar, 54:, 135-45
Abstract: 113Cd-NMR studies have been used to elucidate the structure of the metal-binding sites in mammalian and invertebrate ( Scylla serrata) metallothioneins (MTs). Chemical shift data have shown that all Cd ions are tetrahedrally coordinated to four cysteine thiolate ligands with single cysteinyl sulfurs bridging adjacent metals. Homonuclear decoupling experiments have shown that the 7 g-atoms of metal bound per mole of mammalian protein are located in a three- and a four-metal cluster while the 6 g-atoms of metal in the invertebrate MT are located in two three-metal clusters. The different metal binding affinities of the two mammalian clusters have been determined by 113Cd-NMR. The three-metal cluster prefers Cu greater than Zn greater than Cd whereas exactly the reverse order applies in the four-metal cluster. Proteolytic cleavage of the protein produced a 32-residue fragment which contained the four-metal cluster and demonstrated the presence of two separate domains in the protein. 500 MHz 1H-NMR has been employed to elucidate the arrangement of these metal clusters in the tertiary structure of the protein. The 1H resonances were assigned from their scalar and dipolar connectivities obtained from extensive one and two-dimensional NMR experiments. A specific application of 2D correlation spectroscopy ( COSY ) to the assignment of the 1H resonances in crab MT-1 is discussed. A molecular model, representing the three-dimensional solution structure of this protein, has been constructed based on an analysis of all these data. Detailed structural features of this model are discussed, with particular emphasis on their relationship to the function and evolution of the protein.
Language of Publication: English
Unique Identifier: 84235897

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MeSH Heading (Major): Metallothionein|*AN/GE; Metals|*AN; Nuclear Magnetic Resonance|*
MeSH Heading: Animal; Cadmium; Human; Isotopes; Models, Molecular; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0091-6765
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Isotopes); 0 (Metals); 7440-43-9 (Cadmium); 9038-94-2 (Metallothionein)

Record A22 from database: MEDLINE
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Title: Glutathione mercaptides as transport forms of metals.
Author: Ballatori N
Address: Department of Environmental Medicine, University of Rochester School of Medicine, New York 14642.
Source: Adv Pharmacol, 1994, 27:, 271-98
Abstract: Among the many cellular functions of GSH, the roles of this tripeptide in metal transport, storage, and metabolism have recently received considerable attention. Although these roles had often been overlooked, they are critical for normal cellular metabolism and for protection from xenobiotics. Indeed, a number of the protective and regulatory functions of GSH are related to its ability to chelate reactive metals. GSH functions in the mobilization and delivery of metals between ligands, in the transport of metals across cell membranes, as a source of cysteine for metal binding, and as a reductant or cofactor in redox reactions involving metals. However, the interaction between GSH and metals can also produce or exacerbate cell injury. For example, GSH appears to be involved in the renal accumulation and toxicity of a number of metals, and in the carcinogenicity of chromium. Additional work is clearly needed to identify the mechanisms involved, and to better define the roles of GSH in metal homeostasis.
Language of Publication: English
Unique Identifier: 94347639

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MeSH Heading (Major): Glutathione|*ME; Metals|*ME/TO; Sulfhydryl Compounds|*ME
MeSH Heading: Animal; Biological Transport; Human; Oxidation-Reduction; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, ACADEMIC
ISSN: 1054-3589
Country of Publication: UNITED STATES

Record A23 from database: MEDLINE
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Title: Induction of metallothionein mRNA in HeLa cells by dexamethasone and by heavy metals.
Author: Karin M; Andersen RD; Herschman HR
Address
Source: Eur J Biochem, 1981 Sep 1, 118:3, 527-31
Abstract: Synthesis of metallothionein, a cysteine-rich heavy metal binding protein, is induced in cultured HeLa cells both by the heavy metals Cd2+, Zn2+ and Cu2+, and by the glucocorticoid hormone dexamethasone. The accumulation of [35S]cysteine-labeled metallothionein and the amount of translatable metallothionein mRNA show identical concentration dependences in response to dexamethasone treatment and in response to zinc exposure. Induction of translatable metallothionein mRNA is rapid in response to both the metal and glucocorticoid inducers. Increased synthesis and accumulation of metallothionein in response to either metal or glucocorticoid exposure is regulated by the level of translatable metallothionein mRNA in HeLa cells.
Language of Publication: English
Unique Identifier: 82050551

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MeSH Heading (Major): Dexamethasone|*PD; Metalloproteins|*BI; Metallothionein|*BI; Metals|*PD; RNA, Messenger|*BI
MeSH Heading: Cadmium|PD; Cell-Free System; Copper|PD; Hela Cells|ME; Human; Support, U.S. Gov't, Non-P.H.S.; Wheat; Zinc|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0014-2956
Country of Publication: GERMANY, WEST
CAS Registry/EC Number: 0 (Metalloproteins); 0 (Metals); 0 (RNA, Messenger); 50-02-2 (Dexamethasone); 7440-43-9 (Cadmium); 7440-50-8 (Copper); 7440-66-6 (Zinc); 9038-94-2 (Metallothionein)

Record A24 from database: MEDLINE
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Title: Functional domains of the heavy metal-responsive transcription regulator MTF-1.
Author: Radtke F; Georgiev O; Müller HP; Brugnera E; Schaffner W
Address: Institut fÂur Molekularbiologie II der UniversitÂat ZÂurich, Switzerland.
Source: Nucleic Acids Res, 1995 Jun, 23:12, 2277-86
Abstract: Metallothioneins (MTs) constitute a class of low molecular weight, cysteine-rich, metal binding proteins which are regulated at the level of gene transcription in response to heavy metals and other adverse treatments. We have previously cloned a zinc finger factor (MTF-1) that binds specifically to heavy metal-responsive DNA sequence elements in metallothionein promoters and shown that this factor is essential for basal and heavy metal-induced transcription. Here we report that the C-terminal part of MTF-1 downstream of the DNA binding zinc fingers harbours three different transactivation domains, namely an acidic domain, a proline-rich domain and a domain rich in serine and threonine. When fused to the heterologous DNA binding domain of the yeast factor GAL4 these activation domains function constitutively, i.e. transcription of a GAL4-driven reporter gene is not induced by heavy metals. In search of the region(s) responsible for metal induction, external and internal deletion mutations of mouse and human MTF-1 and chimeric variants thereof were tested with a reporter gene driven by a metal-responsive promoter. The N-terminal part of MTF-1 containing the zinc fingers, which are dependent on zinc for efficient DNA binding, can indeed confer a limited (3- to 4-fold) zinc-responsive transcription when fused to the heterologous activation domain of the viral VP16 protein. Another region containing the acidic and proline-rich activation domains also contributes to metal inducibility, but only in the context of intact MTF-1. This indicates that the activity of MTF-1 results from a complex interplay of different functional domains.
Language of Publication: English
Unique Identifier: 95334383

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MeSH Heading (Major): DNA|*ME; Metallothionein|*GE; Metals|*PD; Transcription Factors|*CH/GE/ME
MeSH Heading: Base Sequence; Binding Sites; Fungal Proteins|CH/GE/ME; Gene Deletion; Hela Cells; Herpes Simplex Virus Protein Vmw65|CH/GE; Human; Hydrogen-Ion Concentration; Molecular Sequence Data; Mutagenesis; Plasmids; Proline|AN; Promoter Regions (Genetics); Recombinant Fusion Proteins|CH/ME; Serine|AN; Threonine|AN; Trans-Activation (Genetics); Zinc Fingers

Publication Type: JOURNAL ARTICLE
ISSN: 0305-1048
Country of Publication: ENGLAND

Record A25 from database: MEDLINE
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Title: Interaction of mammalian sperm nuclear protamines and peptides derived thereof with immobilized zinc.
Author: Bianchi F; Rousseaux Prevost R; Hublau P; Rousseaux J
Address: URA CNRS 409, Lille Cancer Research Institute, France.
Source: Int J Pept Protein Res, 1994 Apr, 43:4, 410-6
Abstract: The interaction of mammalian and human protamines with zinc was studied by immobilized metal ion affinity chromatography (IMAC). The affinity of protamines containing blocked cysteine residues was found to correlate in part with the presence and number of histidine residues in the protamine structure: absence or low affinity of P1 protamines containing 0 or 1 histidine residue; high affinity of human P2 protamine containing 9 histidines. Nevertheless a fraction strongly retained on an IDA-Zn(II) column was observed for P1 protamines with one histidine in the N-terminal sequence (ram and boar protamines). The strong binding was found to be related to the presence of tyrosine, serine and threonine closely spaced to the histidyl side chain. In the case of human protamine P2, the strong retention on the IDA-Zn(II) column seems to result from the additive contribution of all the histidine residues of the molecule. Thus, strong retention of protamines in IMAC seems to depend on an additive contribution of amino-acid side chains: histidine, tyrosine, serine, threonine and perhaps arginine. The high affinity of protamines, more especially P2 protamines, for zinc suggests that this metal ion could play a role for their correct folding and binding to DNA.
Language of Publication: English
Unique Identifier: 94321103

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MeSH Heading (Major): Cell Nucleus|*CH; Peptides|*ME; Protamines|CH/*ME; Spermatozoa|*UL; Zinc|*ME
MeSH Heading: Amino Acid Sequence; Animal; Chromatography, Affinity; Cysteine|CH; Histidine|CH; Human; Male; Molecular Sequence Data; Serine|CH; Sheep; Support, Non-U.S. Gov't; Swine; Tyrosine|CH

Publication Type: JOURNAL ARTICLE
ISSN: 0367-8377
Country of Publication: DENMARK

Record A26 from database: MEDLINE
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Title: Memories of metallothionein.
Author: Kille P; Hemmings A; Lunney EA
Address: Department of Biochemistry, University of Wales College of Cardiff, Wales, UK.
Source: Biochim Biophys Acta, 1994 Apr, 1205:2, 151-61
Abstract: Metallothionein (MT) has provided nature with a small molecule which exhibits multiple facets. The distinct arrangement of cysteine residues which occurs within the two domains of MT confers predisposed metal specificity upon each domain. Furthermore, subtle changes in primary sequence may be built onto the metal cluster scaffold. These not only bestow immunodistinction but may also potentially allow specific members of this family such as MT-III to fulfill unique biological roles. An understanding of how the structures of MT molecules predetermine their biochemical characteristics may allow the design of novel metal-binding molecules specific for the metal ion of choice. Already, using nature as a blueprint, a semi-specific cadmium-binding molecule has been constructed from a polymer of mammalian C-terminal domains. This novel protein has been used to protect tobacco plants from cadmium toxicity. In addition, modeling of biologically active determinants which are located on the external face of MT-III may facilitate the design of small synthetic molecules which mimic the biological activity of MT-III and prevent the distressing effects of memory and speech loss associated with Alzheimer's disease. Memories of metallothionein may yet be something worth remembering!
Language of Publication: English
Unique Identifier: 94206989

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MeSH Heading (Major): Chelating Agents|CH/*ME; Metallothionein|CH/GE/IM/*ME; Metals|*ME
MeSH Heading: Amino Acid Sequence; Animal; Brain Chemistry; Human; Molecular Sequence Data; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE; REVIEW; REVIEW, ACADEMIC
ISSN: 0006-3002
Country of Publication: NETHERLANDS

Record A27 from database: MEDLINE
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Title: Catalase inactivation following photosensitization with tetrasulfonated metallophthalocyanines.
Author: Gantchev TG; van Lier JE
Address: Department of Nuclear Medicine and Radiobiology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
Source: Photochem Photobiol, 1995 Jul, 62:1, 123-34
Abstract: Catalase (CAT) in solution or incorporated in erythrocytes and K562 leukemic cells is inactivated during photosensitization with tetrasulfonated metallophthalocyanines (MePcS4). The effect of added scavengers and D2O showed that both singlet oxygen and free radical species are involved in this process. Evidence was found that direct interactions of ground or excited-stated photosensitizer with CAT are not responsible for CAT inactivation. Specific techniques to probe early damage to the CAT structure involved optical and EPR spectroscopy, HPLC and polyacrylamide gel electrophoresis analyses. Different primary events of photosensitized protein damage included oxidation of cysteine residues as well as other amino acids, as demonstrated by the formation of carbon-centered free radicals and the loss of absorbance at lambda = 275 nm. In parallel, we detected degradation of the CAT heme groups, accompanied by release of Fe(II) ions in solution. These combined phenomena initiate cross-linkages between CAT subunits and subsequent degradation of the protein with formation of irreversible aggregates in solution. Phthalocyanine-mediated photoinactivation of cell-bound CAT results in loss of protection against accumulating H2O2, providing an additional pathway of phototoxicity.
Language of Publication: English
Unique Identifier: 95365432

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MeSH Heading (Major): Catalase|*AI/CH; Indoles|CH/*PD; Metals|CH/*PD; Photosensitizing Agents|*PD
MeSH Heading: Animal; Cattle; Cysteine|CH; Electron Spin Resonance Spectroscopy; Erythrocytes|EN; Free Radicals; Human; Liver|EN; Oxidation-Reduction; Rats; Solutions; Sulfonic Acids|CH; Support, Non-U.S. Gov't; Tumor Cells, Cultured

Publication Type: JOURNAL ARTICLE
ISSN: 0031-8655
Country of Publication: UNITED STATES

Record A28 from database: MEDLINE
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Title: 113Cd nmr study of the metal cluster structure of human liver metallothionein.
Author: Boulanger Y; Armitage IM
Address
Source: J Inorg Biochem, 1982 Oct, 17:2, 147-53
Abstract: Cadmium-113 nuclear magnetic resonance (113Cd nmr) was used to elucidate the structural properties of the cadmium binding sites in human liver metallothionein. The isotopically labeled 113Cd-metallothionein was prepared by the in vitro exchange of the native metals (greater than 94% zinc) for 113CdCl2 during isolation. The two isoproteins, MT-1 and MT-2, showed 113Cd nmr resonances in the chemical shift range 610-670 ppm. The multiplet structure of the resonances is due to two bond scalar interactions between adjacent 113Cd ions linked by cysteine thiolate ligands. Homonuclear 113Cd decoupling experiments allowed the determination of the metal cluster structure, which, similar to the rabbit liver metallothionein, consists of a four- and a three-metal cluster designated cluster A and cluster B, respectively. Chemical shift similarities in the 113Cd nmr spectra of the human, rabbit and calf liver MT-1 and MT-2 are observed, especially for cluster A. Small variations in chemical shifts are explained in terms of differences in the primary structure between the two human isoproteins.
Language of Publication: English
Unique Identifier: 83084856

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MeSH Heading (Major): Liver|*ME; Metalloproteins|*ME; Metallothionein|*ME; Metals|*ME
MeSH Heading: Binding Sites; Cadmium|ME; Chemistry; Female; Human; Middle Age; Nuclear Magnetic Resonance; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0162-0134
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metalloproteins); 0 (Metals); 7440-43-9 (Cadmium); 9038-94-2 (Metallothionein)

Record A29 from database: MEDLINE
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Title: Features of structural zinc in mammalian alcohol dehydrogenase. Site-directed mutagenesis of the zinc ligands.
Author: Jeloková J; Karlsson C; Estonius M; Jörnvall H; Höög JO
Address: Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
Source: Eur J Biochem, 1994 Nov, 225:3, 1015-9
Abstract: All four cysteine ligands to the structural zinc atom of human class-I and class-III alcohol dehydrogenase have been exchanged by site-directed mutagenesis in order to study the importance of the metal in the mammalian enzymes. The cysteine residues were replaced with Ala and Ser, residues that are not able to ligand zinc. All mutations resulted in inactive, unstable enzymes, in contrast to the non-mutated human alcohol dehydrogenases that are easily isolated. Northern-blot analysis revealed the presence of the expected mRNAs from expression plasmids constructed with the different mutated and non-mutated alcohol dehydrogenases, and Western-blot analysis gave faint signals for the mutated recombinant proteins from crude extracts. This verifies that the plasmid constructs are correct, but that the translated, mutated proteins lacking the zinc-stabilized local fold, are subject to rapid degradation. Hence, the results directly illustrate the importance of the structural zinc atom in mammalian alcohol dehydrogenase and confirm it as a component with 'structural' properties. The results are compatible with those from sensitivities to proteases and from the structures of other proteins within the super-family, indicating that the structural role of the zinc atom may involve conservation of interfaces regulating the enzyme quaternary structure.
Language of Publication: English
Unique Identifier: 95045529

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MeSH Heading (Major): Alcohol Dehydrogenase|*CH/GE
MeSH Heading: Amino Acid Sequence; Base Sequence; Binding Sites|GE; Cloning, Molecular; Cysteine|CH; DNA Primers|GE; Escherichia coli|GE; Human; Ligands; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Conformation; Recombinant Proteins|CH/GE; RNA, Messenger|GE; Support, Non-U.S. Gov't; Zinc|CH

Publication Type: JOURNAL ARTICLE
ISSN: 0014-2956
Country of Publication: GERMANY

Record A30 from database: MEDLINE
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Title: The metal ion requirement for activation of latent collagenase from human polymorphonuclear leucocytes.
Author: Macartney HW; Tschesche H
Address
Source: Hoppe Seylers Z Physiol Chem, 1981 Nov, 362:11, 1523-31
Abstract: Latent human PMN leucocyte collagenase (enzyme-inhibitor complex) was shown to require zinc for the property of being activatable by various disulfides [see Macartney, H.W. and Tschesche, H. (1980) FEBS Lett. 119, 327--332]. The active enzyme also requires zinc for activity, indicating a possible participation in the enzyme's reaction mechanism and/or stabilization of the active site. The zinc in the latent enzyme may be removed by dialysis against EDTA, or cysteine. This produces a zinc-free latent enzyme which cannot be activated by any of the disulfide-containing activators. Readdition of zinc to the EDTA-inhibited latent enzyme, at the same concentration as the EDTA, produces an activatable latent enzyme once again. However, excessive zinc concentrations (more than three times the concentration of EDTA) exhibited an inhibitory effect on the activation process. Thereafter the inhibitor cannot be removed by disulfides from the enzyme-inhibitor complex of the latent enzyme. The zinc in the latent enzyme may be replaced by other double-positive metal ions such as cobalt, manganese, magnesium and copper.
Language of Publication: English
Unique Identifier: 82074284

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MeSH Heading (Major): Microbial Collagenase|*BL; Neutrophils|*EN; Zinc|*PD
MeSH Heading: Cations, Divalent; Cobalt|PD; Cysteine|PD; Edetic Acid|PD; Enzyme Activation; Human; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0018-4888
Country of Publication: GERMANY, WEST
CAS Registry/EC Number: EC 3.4.24.3 (Microbial Collagenase); 0 (Cations, Divalent); 4371-52-2 (Cysteine); 60-00-4 (Edetic Acid); 7440-48-4 (Cobalt); 7440-66-6 (Zinc)

Record A31 from database: MEDLINE
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Title: A novel cysteine-rich sequence-specific DNA-binding protein interacts with the conserved X-box motif of the human major histocompatibility complex class II genes via a repeated Cys-His domain and functions as a transcriptional repressor.
Author: Song Z; Krishna S; Thanos D; Strominger JL; Ono SJ
Address: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Source: J Exp Med, 1994 Nov, 180:5, 1763-74
Abstract: The class II major histocompatibility complex (MHC) molecules function in the presentation of processed peptides to helper T cells. As most mammalian cells can endocytose and process foreign antigen, the critical determinant of an antigen-presenting cell is its ability to express class II MHC molecules. Expression of these molecules is usually restricted to cells of the immune system and dysregulated expression is hypothesized to contribute to the pathogenesis of a severe combined immunodeficiency syndrome and certain autoimmune diseases. Human complementary DNA clones encoding a newly identified, cysteine-rich transcription factor, NF-X1, which binds to the conserved X-box motif of class II MHC genes, were obtained, and the primary amino acid sequence deduced. The major open reading frame encodes a polypeptide of 1,104 amino acids with a symmetrical organization. A central cysteine-rich portion encodes the DNA-binding domain, and is subdivided into seven repeated motifs. This motif is similar to but distinct from the LIM domain and the RING finger family, and is reminiscent of known metal-binding regions. The unique arrangement of cysteines indicates that the consensus sequence CX3CXL-XCGX1-5HXCX3CHXGXC represents a novel cysteine-rich motif. Two lines of evidence indicate that the polypeptide encodes a potent and biologically relevant repressor of HLA-DRA transcription: (a) overexpression of NF-X1 from a retroviral construct strongly decreases transcription from the HLA-DRA promoter; and (b) the NF-X1 transcript is markedly induced late after induction with interferon gamma (IFN-gamma), coinciding with postinduction attenuation of HLA-DRA transcription. The NF-X1 protein may therefore play an important role in regulating the duration of an inflammatory response by limiting the period in which class II MHC molecules are induced by IFN-gamma.
Language of Publication: English
Unique Identifier: 95053707

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MeSH Heading (Major): DNA-Binding Proteins|CH/GE/*PH; Genes, MHC Class II|*; Repressor Proteins|CH/GE/*PH
MeSH Heading: Amino Acid Sequence; Base Sequence; Conserved Sequence; Cysteine; DNA, Complementary|IP; Human; HLA-DR Antigens|GE; Interferon Type II|PD; Molecular Sequence Data; RNA, Messenger|BI; Structure-Activity Relationship; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Transcription, Genetic

Publication Type: JOURNAL ARTICLE
ISSN: 0022-1007
Country of Publication: UNITED STATES

Record A32 from database: MEDLINE
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Title: Characterization of interactions of nitric oxide with human hemoglobin A by infrared spectroscopy.
Author: Sampath V; Zhao XJ; Caughey WS
Address: Department of Biochemistry and Molecular Biology, Colarado State University, Fort Collins 80523.
Source: Biochem Biophys Res Commun, 1994 Jan, 198:1, 281-7
Abstract: Infrared spectra permit direct measurements of cysteine thiols as well as nitric oxide bound to heme iron in human hemoglobin A nitrosyl. A single symmetric N-O stretch band of nitric oxide bound to Fe2+ is detected amid strong water and protein bands in the Hb14N16O minus Hb15N16O difference spectrum. Nitric oxide accepts electron density from metal in bent-end-on FeI2+)-14N-16O (nu NO = 1616.5 cm-1) and donates electron density to metal in linear Fe(3+)-14N-16O (nu NO = 1925 cm-1). S-H stretch bands reveal that changes in protein conformation occur at alpha-104, beta-93, and beta-112 cysteines upon conversion of deoxyHb to HbNO but that no reactions of thiols with NO occur. Furthermore, no infrared band for S-nitrosothiol is detected. Changes in amide I spectra reflect NO binding induced changes in protein secondary structure.
Language of Publication: English
Unique Identifier: 94121643

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MeSH Heading (Major): Hemoglobin A|*CH/ME; Nitric Oxide|*CH/ME
MeSH Heading: Binding Sites; Cysteine; Human; Iron|AN; Protein Conformation; Spectrophotometry, Infrared|MT; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES

Record A33 from database: MEDLINE
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Title: Mutation of the metal-bridging proton-donor His63 residue in human Cu, Zn superoxide dismutase. Biochemical and biophysical analysis of the His63-->Cys mutant.
Author: Banci L; Bertini I; Borsari M; Viezzoli MS; Hallewell RA
Address: Department of Chemistry, University of Florence, Italy.
Source: Eur J Biochem, 1995 Aug, 232:1, 220-5
Abstract: The bridging His63 residue in human Cu, Zn superoxide dismutase, which binds both metals, has been replaced by a Cys residue. The mutant protein has been purified from Escherichia coli and appears to be a normal dimer. Spectroscopic techniques (electronic spectroscopies, EPR, nuclear magnetic relaxation dispersion) show that Cys63 binds the zinc ion, but not the copper ion, and that the latter is probably five co-ordinated with three histidine ligands and two water molecules. The reduction potential of the copper ion in the Cu2+/Cu+ pair decreases from 0.41 V to 0.27 V at neutral pH but still remains intermediate between those of the O2/O2- and O2-/H2O2 pairs so that copper can both oxidize and reduce the O2- substrate, a requirement for dismutase activity. The enzyme binds the substrate-analogue azide (N3-), which displaces one water molecule, with near normal affinity, whereas the enzyme activity with the O2- substrate is reduced to less than 1% of wild-type levels at pH 7.8. The properties of the mutant enzyme are discussed in relation to the superoxide-copper electron transfer process and to the catalytic mechanism.
Language of Publication: English
Unique Identifier: 96048050

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MeSH Heading (Major): Superoxide Dismutase|CH/*GE/ME
MeSH Heading: Copper|ME; Cysteine|ME; Enzyme Activation|GE; Histidine|ME; Human; Mutation; Protons; Support, Non-U.S. Gov't; Zinc|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0014-2956
Country of Publication: GERMANY

Record A34 from database: MEDLINE
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Title: Proteolytic processing of Alzheimer's disease beta A4 amyloid precursor protein in human platelets.
Author: Li QX; Evin G; Small DH; Multhaup G; Beyreuther K; Masters CL
Address: Department of Pathology, University of Melbourne, Parkville, Victoria, Australia.
Source: J Biol Chem, 1995 Jun, 270:23, 14140-7
Abstract: The processing of amyloid precursor protein (APP) and production of beta A4 amyloid are events likely to influence the development and progression of Alzheimer's disease, since beta A4 is the major constituent of amyloid deposited in this disorder. Our previous studies showed that human platelets contain full-length APP (APPFL) and are a suitable substrate to study normal APP processing. In the present study, we show that a 22-kDa beta A4-containing carboxyl-terminal fragment (22-CTF) of APP is present in unstimulated platelets. Both APPFL and 22-CTF are proteolytically degraded when platelets are activated with thrombin, collagen, or calcium ionophore A23187. Complete cleavage of APPFL and 22-CTF require the presence of extracellular calcium. Following stimulation in the presence of calcium, a new CTF of 17 kDa is generated, and the NH2-terminal epitope of beta A4 amyloid is lost. Preincubation of platelets with the cell-permeable cysteine protease inhibitors calpeptin, (2S,3S)-trans-epoxysuccinyl-L-leucyl-amido-3-methylbutane ethyl ester (E64d), Na alpha-p-tosyl-L-lysine chloromethyl ketone, or calcium chelator EGTA before platelet stimulation inhibits the degradation of both APPFL and 22-CTF. Divalent metal ions including zinc, copper, and cobalt inhibit the degradation of APPFL and 22-CTF. This study suggests that a calcium-dependent neutral cysteine protease is involved in the proteolytic processing of an amyloidogenic species of APP in human platelets.
Language of Publication: English
Unique Identifier: 95294022

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MeSH Heading (Major): Amyloid beta-Protein Precursor|*ME; Blood Platelets|*ME; Cysteine Proteinases|*PH
MeSH Heading: Calcimycin|PD; Calcium|PD; Calpain|PD; Egtazic Acid|PD; Human; Peptide Fragments|AN; Protease Inhibitors|PD; Support, Non-U.S. Gov't; Zinc|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES

Record A35 from database: MEDLINE
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Title: EEA1, an early endosome-associated protein. EEA1 is a conserved alpha-helical peripheral membrane protein flanked by cysteine "fingers" and contains a calmodulin-binding IQ motif.
Author: Mu FT; Callaghan JM; Steele Mortimer O; Stenmark H; Parton RG; Campbell PL; McCluskey J; Yeo JP; Tock EP; Toh BH
Address: Department of Pathology, National University of Singapore.
Source: J Biol Chem, 1995 Jun, 270:22, 13503-11
Abstract: Early endosomes are cellular compartments receiving endocytosed material and sorting them for vesicular transport to late endosomes and lysosomes or for recycling to the plasma membrane. We have cloned a human cDNA encoding an evolutionarily conserved 180-kDa protein on early endosomes named EEA1 (Early Endosome Antigen1). EEA1 is associated with early endosomes since it co-localizes by immunofluorescence with the transferrin receptor and with Rab5 but not with Rab7. Immunoelectron microscopy shows that it is associated with tubulovesicular early endosomes containing internalized bovine serum albumin-gold. EEA1 is a hydrophilic peripheral membrane protein present in cytosol and membrane fractions. It partitions in the aqueous phase after Triton X-114 solubilization and is extracted from membranes by 0.3 M NaCl. It is a predominantly alpha-helical protein sharing 17-20% sequence identity with the myosins and contains a calmodulin-binding IQ motif. It is flanked by metal-binding, cysteine "finger" motifs. The COOH-terminal fingers, Cys-X2-Cys-X12-Cys-X2-Cys and Cys-X2-Cys-X16-Cys-X2-Cys, are present within a region that is strikingly homologous with Saccharomyces cerevisiae FAB1 protein required for endocytosis and with Caenorhabditis elegans ZK632. These fingers also show limited conservation with S. cerevisiae VAC1, Vps11, and Vps18p proteins implicated in vacuolar transport. We propose that EEA1 is required for vesicular transport of proteins through early endosomes and that its finger motifs are required for this activity.
Language of Publication: English
Unique Identifier: 95286647

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MeSH Heading (Major): Calmodulin-Binding Proteins|*GE/ME; Cysteine|*ME; Endosomes|*ME; Membrane Proteins|*GE/IM/ME
MeSH Heading: Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; Cytoplasm|IM; DNA, Complementary; G-Proteins|ME; Hela Cells; Human; Immune Sera; Mice; Microscopy, Immunoelectron; Molecular Sequence Data; Protein Binding; Rabbits; Receptors, Transferrin|ME; Recombinant Proteins|GE/IM/ME; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't; 3T3 Cells

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES

Record A36 from database: MEDLINE
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Title: Solution structure of a cysteine rich domain of rat protein kinase C.
Author: Hommel U; Zurini M; Luyten M
Address: SANDOZ PHARMA AG, Basel, Switzerland.
Source: Nat Struct Biol, 1994 Jun, 1:6, 383-7
Abstract: Intracellular protein phosphorylation by protein kinase C (PKC) plays a major role in the translation of extracellular signals into cellular events. Speculations on the structural basis for PKC activation are based on sequence homology between their cysteine-rich domains (CRD) and the DNA-binding 'zinc-fingers'. We produced a fragment comprising the second CRD (CRD2) of rat PKC-alpha and determined its three-dimensional structure in solution by NMR spectroscopy. This revealed that CRD2 adopts a globular fold allowing two non-consecutive sets of zinc-binding residues to form two separate metal-binding sites. The fold is different to those previously proposed and allows insight into the molecular topology of a family of homologous proteins.
Language of Publication: English
Unique Identifier: 95393166

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MeSH Heading (Major): Models, Molecular|*; Protein Conformation|*; Protein Kinase C|*CH
MeSH Heading: Amino Acid Sequence; Animal; Binding Sites; Comparative Study; Consensus Sequence; Cysteine; Drosophila melanogaster|ME; Enzyme Activation; Fungal Proteins|CH; Human; Molecular Sequence Data; Nerve Tissue Proteins|CH; Nuclear Magnetic Resonance; Phosphorylation; Phosphotransferases (Alcohol Group Acceptor)|CH; Protein-Serine-Threonine Kinases|CH; Proto-Oncogene Proteins|CH; Rats; Recombinant Fusion Proteins|CH; Saccharomyces cerevisiae|ME; Sequence Alignment; Sequence Homology, Amino Acid; Solutions; Swine; Zinc Fingers

Publication Type: JOURNAL ARTICLE
ISSN: 1072-8368
Country of Publication: UNITED STATES

Record A37 from database: MEDLINE
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Title: Metal binding 'finger' structures in the glucocorticoid receptor defined by site-directed mutagenesis.
Author: Severne Y; Wieland S; Schaffner W; Rusconi S
Address: Institut für Molekularbiologie II, Universität Zürich, Switzerland.
Source: EMBO J, 1988 Aug, 7:8, 2503-8
Abstract: The glucocorticoid receptor and the other members of the steroid receptor super-family share a highly conserved, cysteine-rich region which coincides with the DNA binding/transactivating domain. It has been postulated that this region is folded into two 'zinc finger' structures, similar to those originally reported for the transcription factor TFIIIA. The first potential finger domain contains four conserved cysteines and one conserved histidine, while the second contains five conserved cysteines. Using site-directed mutagenesis, we have analysed the consequences of altering the proposed finger-like structures. Our results show that most of the mutations affecting the conserved cysteines result in a total loss of glucocorticoid receptor function. In one important exception, however, a conserved cysteine (Cys500) is dispensable for glucocorticoid receptor activity and therefore cannot be involved in complexing a metal ion to form a finger structure. Moreover, the replacement of either Cys476 or Cys482 by His residues maintains partial in vivo activity of the glucocorticoid receptor, while their exchange for an alanine or serine residue, respectively, eliminates receptor function. These results support, at a genetic level, the involvement of cysteines of the glucocorticoid receptor DNA binding domain in metal ion complexation and define the candidate residues involved in such coordination.
Language of Publication: English
Unique Identifier: 89052664

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MeSH Heading (Major): Cysteine|*ME; Histidine|*ME; Receptors, Glucocorticoid|*GE/ME; Zinc|*ME
MeSH Heading: Amino Acid Sequence; Cell Line; Gene Expression Regulation; Hela Cells; Human; Molecular Sequence Data; Mutation; Support, Non-U.S. Gov't; Transfection

Publication Type: JOURNAL ARTICLE
ISSN: 0261-4189
Country of Publication: ENGLAND
CAS Registry/EC Number: 0 (Receptors, Glucocorticoid); 4371-52-2 (Cysteine); 7006-35-1 (Histidine); 7440-66-6 (Zinc)

Record A38 from database: MEDLINE
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Title: Heavy metal inhibition of carnitine acetyltransferase activity in human placental syncytiotrophoblast: possible site of action of HgCl2, CH3HgCl, and CdCl2.
Author: Shoaf AR; Jarmer S; Harbison RD
Address
Source: Teratog Carcinog Mutagen, 1986, 6:5, 351-60
Abstract: The effect of the heavy metal toxicants HgCl2, CH3HgCl, and CdCl2 on the acetylating activity of membranous carnitine acetyltransferase (CarAc) in membrane vesicles from the maternal surface of human placental syncytiotrophoblast has been investigated. CarAc was inhibited by inorganic and organic mercury and cadmium. Carnitine acetylation was inhibited by as little as 5 microM mercury, with complete inhibition at 50 microM inorganic and organic mercury. Inhibition by cadmium was incomplete (less than 60%) at 500 microM CdCl2. Kinetic studies using Hanes plots revealed a mixed type of inhibition of CarAc by the metals. Cysteine preincubation decreased the amount of inhibition of CarAc by the metals. These results indicate that the inhibition of CarAc by heavy metals occurs by binding of the sulfhydryl on the enzyme by the metals. This interaction may be a mechanism of the heavy metal-induced fetotoxicity.
Language of Publication: English
Unique Identifier: 87070502

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MeSH Heading (Major): Acetyltransferases|*AI; Cadmium|AI/*PD; Carnitine Acetyltransferase|*AI; Mercury|AI/*PD; Trophoblast|*EN
MeSH Heading: Cysteine|PD; Human; In Vitro; Kinetics; Mercuric Chloride|PD; Methylmercury Compounds|PD; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0270-3211
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 2.3.1. (Acetyltransferases); EC 2.3.1.7 (Carnitine Acetyltransferase); 0 (Methylmercury Compounds); 10108-64-2 (Cadmium Chloride); 115-09-3 (methylmercuric chloride); 4371-52-2 (Cysteine); 7439-97-6 (Mercury); 7440-43-9 (Cadmium); 7487-94-7 (Mercuric Chloride)

Record A39 from database: MEDLINE
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Title: Histamine as a ligand in blood plasma. Part 6. Aspartate and glutamate as possible partner ligands for zinc and histamine to favour histamine catabolism.
Author: Berthon G; Germonneau P
Address
Source: Agents Actions, 1982 Dec, 12:5-6, 619-29
Abstract: The hypothesis was recently put forward that the diffusion of plasma histamine into the environmental tissues in which the mediator is catabolized, may occur passively in the form of the zinc-histamine-cysteinate complex. In accordance with this hypothesis, any partner ligand for zinc and histamine in which raising plasma concentration would entail a better mobilization of histamine into neutral diffusable metal complexes would also favour the histamine catabolism. Such a role was envisaged in the present work for aspartate and glutamate. Their efficiency in that respect was tested on the basis of computer simulations using the equilibrium constants of the corresponding zinc-histamine-aspartate and zinc-histamine-glutamate complexes, which were determined beforehand under the plasma conditions of temperature, ionic strength and isotonicity. It was established that aspartate and glutamate plasma concentrations should be raised 1000 and 400 times over their respective normal levels before the combination of each of these amino-acids with zinc within the same increase ratio becomes more efficient than zinc ions alone.
Language of Publication: English
Unique Identifier: 83149369

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MeSH Heading (Major): Aspartic Acid|*BL; Glutamates|*BL; Histamine|*BL; Zinc|*BL
MeSH Heading: Cysteine|BL; Diffusion; Human; Ligands

Publication Type: JOURNAL ARTICLE
ISSN: 0065-4299
Country of Publication: SWITZERLAND
CAS Registry/EC Number: 0 (Glutamates); 0 (Ligands); 4371-52-2 (Cysteine); 51-45-6 (Histamine); 56-84-8 (Aspartic Acid); 56-86-0 (Glutamic Acid); 7440-66-6 (Zinc)

Record A40 from database: MEDLINE
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Title: Exposure of hydrophobic moieties promotes the selective degradation of hydrogen peroxide-modified hemoglobin by the multicatalytic proteinase complex, proteasome.
Author: Giulivi C; Pacifici RE; Davies KJ
Address: Institute for Toxicology, University of Southern California, Los Angeles 90033.
Source: Arch Biochem Biophys, 1994 Jun, 311:2, 329-41
Abstract: The physiologically relevant stress of a flux of H2O2 increased hemoglobin (Hb) degradation in red blood cells (RBC) and increased the proteolytic susceptibility of Hb in vitro. After exposure to low H2O2 flux rates (6-32 microM/min) Hb exhibited increased exposure of hydrophobic (Trp, Met) and basic (Lys) amino acid R groups, increased hydrophobicity, and increased proteolytic susceptibility during subsequent incubation with RBC extracts, a partially purified preparation called Fraction II (which retains all of the proteolytic activities of RBC extracts), or the purified 670-kDa RBC multicatalytic proteinase complex proteasome. Hydrophobicity was measured by butyl-Sepharose hydrophobic interaction chromatography, by the free energy of transfer from water to ethanol, and by heat denaturation assays. Proteolytic susceptibility was measured by release of free alanine, by fluorescamine-reactive free amino groups, and by release of acid-soluble radioactivity from radiolabeled Hb. Low H2O2 flux rates also caused significant charge changes in Hb (isoelectric focusing gels) and extensive noncovalent aggregation (presumably due to increased hydrophobic interactions) but only limited covalent cross-linking (comparison of sodium dodecyl sulfate-polyacylamide gel electrophoresis (SDS-PAGE) and nondenaturing PAGE). Exposure to higher H2O2 flux rates (56-120 microM/min) caused progressive oxidative destruction of exposed hydrophobic amino acids, decreased hydrophobicity as judged by butyl-Sepharose chromatography and heat denaturation assays, increased hydrophilicity as judged by measurements of the free energy of transfer (delta G') from water to ethanol, and decreased proteolytic susceptibility during incubation with RBC extracts, Fraction II, or purified proteasome. High H2O2 flux rates also caused further charge changes and the extensive formation of covalently cross-linked Hb molecules. Linear regression analyses revealed correlations of 0.8-0.99 for the relationship between Hb hydrophobicity and proteolytic susceptibility for both Fraction II and proteasome. Inhibitor studies and SDS activation experiments indicate that proteasome is responsible for most of the Hb degradation during exposure of RBC to H2O2. Previous work yielded essentially identical conclusions for Hb exposed to hydroxyl radicals (R. E. Pacifici, Y. Kono, and K. J. A. Davies, J. Biol. Chem. 268, 15405-15411, 1993). Thus, nonspecific oxidation by .OH and site-specific (metal-catalyzed) oxidation by H2O2 both yield a more hydrophobic Hb molecule with increased proteolytic susceptibility. We propose that increased exposure of hydrophobic, and perhaps basic, amino acids is the general common cause for degradation of oxidized proteins.(ABSTRACT TRUNCATED AT 400 WORDS)
Language of Publication: English
Unique Identifier: 94263209

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MeSH Heading (Major): Cysteine Proteinases|*ME; Erythrocytes|DE/*ME; Hemoglobins|CH/IP/*ME; Hydrogen Peroxide|*PD; Multienzyme Complexes|*ME; Oxyhemoglobins|CH/IP/*ME
MeSH Heading: Animal; Cattle; Chromatography, High Pressure Liquid; Electrophoresis, Polyacrylamide Gel; Glucose Oxidase|PD; Human; Isoelectric Focusing; Kinetics; Protein Denaturation; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0003-9861
Country of Publication: UNITED STATES

Record A41 from database: MEDLINE
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Title: Identification of a putative antioxidant response element in the 5'-flanking region of the human gamma-glutamylcysteine synthetase heavy subunit gene.
Author: Mulcahy RT; Gipp JJ
Address: Department of Human Oncology, University of Wisconsin Medical School, Madison 53792, USA.
Source: Biochem Biophys Res Commun, 1995 Apr, 209:1, 227-33
Abstract: We have cloned the human gamma-glutamylcysteine synthetase heavy subunit gene (GCSh) from a P1 library and isolated a 5.5kb fragment (P1-GCS5') from the 5'-end of the P1 clone. P1-GCS5' has been sequenced from -1460 to +547. Multiple transcription start sites were identified by primer extension and S1 nuclease protection. Two start sites were identified by primer extension analysis within 23 bp (+1 and +10) of a consensus TATAAAA box; all sequences were numbered relative to the 5'-most of these two sites. Two additional major start sites were identified at -106 and +398. This latter site was the most prominent of all the initiation sites. In addition to a TATA box, the promoter contains a CCAAT box at -125 and GC boxes up- and down-stream of the TATAAAA. In addition, the first few hundred base pairs of the sequence are highly GC-rich (approximately 75%). This sequence also contains several Sp-1 binding sites, a consensus AP-1 site and several AP-1-like binding sites, as well as putative AP-2 sites. A consensus metal responsive element (MRE) was identified at position +198. Sequence analysis also identified a putative core (5'-TGACnnnGCA-3') antioxidant response element (ARE) at -862 to -853. As is typical of other AREs, a second AP-1-like sequence is located adjacent to the core sequence. These results suggest that GCSh gene expression in response to oxidative challenge may be regulated through an antioxidant response element similar to those recently detected in the promoter region of several Phase II enzymes.
Language of Publication: English
Unique Identifier: 95243932

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MeSH Heading (Major): Antioxidants|*PD; Glutamate-Cysteine Ligase|*GE; Regulatory Sequences, Nucleic Acid|*
MeSH Heading: Base Sequence; Cloning, Molecular; DNA, Complementary; Human; Molecular Sequence Data; Promoter Regions (Genetics); Support, U.S. Gov't, P.H.S.; Transcription, Genetic

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES

Record A42 from database: MEDLINE
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Title: Tumor-promoting phorbol esters and cell proliferation stimulate secretion of basement membrane (type IV) collagen-degrading metalloproteinase by human fibroblasts.
Author: Salo T; Turpeenniemi-Hujanen T; Tryggvason K
Address
Source: J Biol Chem, 1985 Jul 15, 260:14, 8526-31
Abstract: The secretion of a type IV collagen-specific proteinase is stimulated in cultured human skin fibroblasts by the phorbol ester tumor promoter 12-O-tetradecanoyl phorbol 13-acetate (TPA) and during cell proliferation. Exposure of the cells at the late log phase of growth to 10(-9) to 10(-6) M TPA resulted in the secretion of type IV collagenase activity to the medium, this effect being reversible. Incubation of intact type IV procollagen with TPA-induced fibroblast medium protein produced six peptides, four of which corresponded in size to the fragments produced by a type IV collagen-specific collagenase (Fessler, L., Duncan, K., Fessler, J., Salo, T., and Tryggvason (1984) J. Biol. Chem. 259, 9783-9789). The TPA-induced type IV collagen-degrading enzyme could be activated by trypsin, was inhibited by EDTA, but was not affected by soybean trypsin inhibitor, N-ethylmaleimide, aprotinin, or cysteine. Therefore, in human skin fibroblasts, TPA can induce a type IV collagen-specific, metal-dependent collagenase as was previously described in some invasive tumor cells. Furthermore, another metalloprotease is apparently secreted under the same conditions of TPA exposure. The production of metal-dependent, type IV collagen-degrading activity was also studied at different stages of cellular proliferation. In early log phase, a significant amount of enzyme activity was observed in the control cell medium; this activity disappeared during both late log and stationary growth phases. This activity could be markedly increased by the addition of 10(-8) M TPA to the culture medium. The production of matrix-degrading proteinases is therefore likely to be associated with rapid cell proliferation in both transformed and untransformed cells.
Language of Publication: English
Unique Identifier: 85234571

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MeSH Heading (Major): Microbial Collagenase|*ME; Peptide Peptidohydrolases|*ME; Phorbols|*PD; Skin|CY/*EN; Tetradecanoylphorbol Acetate|*PD
MeSH Heading: Aprotinin|PD; Basement Membrane|EN; Cell Division|DE; Culture Media; Cysteine|PD; Edetic Acid|PD; Ethylmaleimide|PD; Fibroblasts|EN/UL; Human; Procollagen|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Time Factors; Trypsin|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.4.- (Peptide Peptidohydrolases); EC 3.4.21.4 (Trypsin); EC 3.4.24 (Metalloproteinases); EC 3.4.24.3 (Microbial Collagenase); 0 (Culture Media); 0 (Phorbols); 0 (Procollagen); 128-53-0 (Ethylmaleimide); 16561-29-8 (Tetradecanoylphorbol Acetate); 4371-52-2 (Cysteine); 60-00-4 (Edetic Acid); 9087-70-1 (Aprotinin)

Record A43 from database: MEDLINE
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Title: Immobilized-enzyme rate-determination method for glucose analysis.
Author: Sokol L; Garber C; Shults M; Updike S
Address
Source: Clin Chem, 1980 Jan, 26:1, 89-92
Abstract: We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surface by use of paraformaldehyde. The immobilized-enzyme method is compared with a similar solution-enzyme method and with the National Glucose Reference method. The immobilized enzyme method compares favorably with the solution-enzyme method and offers the advantages of simplicity, economy of enzyme, and linearity over a greater range of concentration.
Language of Publication: English
Unique Identifier: 80090462

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MeSH Heading (Major): Blood Glucose|*AN; Enzymes, Immobilized|*; Glucose Oxidase|*
MeSH Heading: Ascorbic Acid; Bilirubin; Comparative Study; Cysteine; Hemoglobins; Hexokinase; Human; Methods; Solubility; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0009-9147
Country of Publication: UNITED STATES

Record A44 from database: MEDLINE
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Title: Involvement of cysteine, serotonin and their analogues in peroxidase-oxidase reactions.
Author: Svensson BE
Address: Research and Development Department, Södertälje, Sweden.
Source: Chem Biol Interact, 1989, 70:3-4, 305-21
Abstract: Myeloperoxidase-oxidase reactions with close to physiological concentrations of thiols and phenols were studied. Cysteine was shown to be a myeloperoxidase-oxidase substrate when catalytic amounts of serotonin were added as cosubstrate. Penicillamine could be substituted for cysteine and acetaminophen could be substituted for serotonin. The properties of these peroxidase-oxidase reactions, e.g. the dependence on substrate and myeloperoxidase concentration, reduced oxygen species, metal ions and pH, were studied. Also, eosinophil, lacto- and horseradish peroxidase could catalyse these reactions.
Language of Publication: English
Unique Identifier: 89304199

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MeSH Heading (Major): Oxidoreductases|*ME; Peroxidases|*ME
MeSH Heading: Animal; Cysteine|ME; Human; Oxygen Consumption; Peroxidase|ME; Phenols|ME; Serotonin|ME; Sulfhydryl Compounds|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0009-2797
Country of Publication: NETHERLANDS
CAS Registry/EC Number: EC 1. (Oxidoreductases); EC 1.11.1. (Peroxidases); EC 1.11.1.7 (Peroxidase); 0 (Phenols); 0 (Sulfhydryl Compounds); 4371-52-2 (Cysteine); 50-67-9 (Serotonin)

Record A45 from database: MEDLINE
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Title: Determination and metabolism of dithiol chelating agents. VI. Isolation and identification of the mixed disulfides of meso-2,3-dimercaptosuccinic acid with L-cysteine in human urine.
Author: Maiorino RM; Bruce DC; Aposhian HV
Address: Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721.
Source: Toxicol Appl Pharmacol, 1989 Feb, 97:2, 338-49
Abstract: Virtually nothing is known about the biotransformation of the heavy metal chelating agent, meso-2,3-dimercaptosuccinic acid (DMSA). Two fasted, normal, young men were given 10.0 mg DMSA/kg po, and their urines were collected over a 14-hr period. Urine samples were analyzed, before and after electrolytic reductive treatment, for DMSA and its biotransformants using bromobimane derivatization, HPLC separation, and fluorescence detection. Metabolites were isolated by HPLC, ion-pairing extraction, ion-exchange extraction, and TLC. By 14 hr after DMSA administration, 87% of the total DMSA and 95% of the total L-cysteine found in urine consisted of altered forms of these compounds. The urinary excretion of altered DMSA, at 1, 2, 4, 6, 9, and 14 hr after administration of DMSA, when compared to the urinary excretion of altered L-cysteine had a correlation coefficient of 0.952 and p less than 0.003. Approximately 90% of the altered DMSA excreted in the 2- to 4-hr urine was found in disulfide linkage with L-cysteine. The remaining 10% was found as cyclic disulfides of DMSA. Of the mixed disulfides found in 4- to 6-hr urine, 97% consisted of two L-cysteine residues per one DMSA and the remaining 3% consisted of one L-cysteine per one DMSA. The 2:1 mixed disulfides (97%) were isolated as three distinct species by TLC, consisting of 77, 12, and 8% of the total mixed disulfides found. In addition to the novelty of these biotransformants of DMSA, the DMSA-cysteine mixed disulfides indicate a thiol-disulfide interchange between DMSA and L-cystine. The discovery of the formation of these water soluble DMSA-cysteine mixed disulfides should encourage the evaluation of DMSA in the treatment of cystinuria.
Language of Publication: English
Unique Identifier: 89162496

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MeSH Heading (Major): Cysteine|*ME; Succimer|*ME; Sulfhydryl Compounds|*ME
MeSH Heading: Adult; Biotransformation; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Copper|UR; Cystinuria|DT; Disulfides|ME; Human; Lead|UR; Male; Species Specificity; Support, U.S. Gov't, P.H.S.; Zinc|UR

Publication Type: JOURNAL ARTICLE
ISSN: 0041-008X
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Disulfides); 0 (Sulfhydryl Compounds); 304-55-2 (Succimer); 4371-52-2 (Cysteine); 7439-92-1 (Lead); 7440-50-8 (Copper); 7440-66-6 (Zinc)

Record A46 from database: MEDLINE
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Title: Structural and functional characterization of human immunodeficiency virus tat protein.
Author: Ruben S; Perkins A; Purcell R; Joung K; Sia R; Burghoff R; Haseltine WA; Rosen CA
Address: Department of Molecular Oncology, Roche Institute of Molecular Biology, Nutley, New Jersey.
Source: J Virol, 1989 Jan, 63:1, 1-8
Abstract: Site-directed mutagenesis was used to identify functional domains present within the human immunodeficiency virus (HIV) tat protein. Transient cotransfection experiments showed that derivatives of tat protein with amino acid substitutions either at the amino-terminal end or at cysteine residue 22, 37, 27, or 25 were no longer able to transactivate HIV long terminal repeat-directed gene expression. Incubation of Tat expressed in Escherichia coli with zinc demonstrated that both authentic Tat and cysteine mutation derivatives could form metal-protein complexes. The tat proteins that contained alterations within the cluster of positively charged amino acid residues retained their ability to transactivate gene expression, albeit at markedly reduced levels. Indirect immunofluorescence showed that the authentic tat protein and the amino-terminal and cysteine substitution mutants all localized in the nucleus, with accumulation being most evident in the nucleolus. In contrast, nuclear accumulation was greatly reduced with the basic-substitution mutations. Consistent with this result, a fusion protein that contained amino acids GRKKR, derived from the basic region, fused to the amino-terminal end of beta-galactosidase also accumulated within the nucleus. These results demonstrate that the 14-kilodalton tat protein contains at least three distinct functional domains affecting localization and transactivation.
Language of Publication: English
Unique Identifier: 89068819

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MeSH Heading (Major): HIV|AN/*GE/UL; Transcription Factors|AN/*GE/ME
MeSH Heading: Amino Acid Sequence; Cell Line; Cell Nucleolus|AN; Cell Nucleus|AN; Cloning, Molecular; Cysteine|ME; Fluorescent Antibody Technique; Gene Expression Regulation; Hela Cells; Human; Molecular Sequence Data; Mutation; Support, U.S. Gov't, P.H.S.; Transfection; Zinc|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0022-538X
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Gene Products, tat); 0 (Transcription Factors); 4371-52-2 (Cysteine); 7440-66-6 (Zinc)

Record A47 from database: MEDLINE
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Title: The extended environment of mononuclear metal centers in protein structures.
Author: Karlin S; Zhu ZY; Karlin KD
Address: Department of Mathematics, Stanford University, Stanford, CA 94305-2125, USA. fd.zgg@forsythe.stanford.edu
Source: Proc Natl Acad Sci U S A, 1997 Dec, 94:26, 14225-30
Abstract: The objectives of this and the following paper are to identify commonalities and disparities of the extended environment of mononuclear metal sites centering on Cu, Fe, Mn, and Zn. The extended environment of a metal site within a protein embodies at least three layers: the metal core, the ligand group, and the second shell, which is defined here to consist of all residues distant less than 3.5 A from some ligand of the metal core. The ligands and second-shell residues can be characterized in terms of polarity, hydrophobicity, secondary structures, solvent accessibility, hydrogen-bonding interactions, and membership in statistically significant residue clusters of different kinds. Findings include the following: (i) Both histidine ligands of type I copper ions exclusively attach the Ndelta1 nitrogen of the histidine imidazole ring to the metal, whereas histidine ligands for all mononuclear iron ions and nearly all type II copper ions are ligated via the Nepsilon2 nitrogen. By contrast, multinuclear copper centers are coordinated predominantly by histidine Nepsilon2, whereas diiron histidine contacts are predominantly Ndelta1. Explanations in terms of steric differences between Ndelta1 and Nepsilon2 are considered. (ii) Except for blue copper (type I), the second-shell composition favors polar residues. (iii) For blue copper, the second shell generally contains multiple methionine residues, which are elements of a statistically significant histidine-cysteine-methionine cluster. Almost half of the second shell of blue copper consists of solvent-accessible residues, putatively facilitating electron transfer. (iv) Mononuclear copper atoms are never found with acidic carboxylate ligands, whereas single Mn2+ ion ligands are predominantly acidic and the second shell tends to be mostly buried. (v) The extended environment of mononuclear Fe sites often is associated with histidine-tyrosine or histidine-acidic clusters.
Language of Publication: English
Unique Identifier: 98070733

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MeSH Heading (Major): Metals|*CH; Protein Conformation|*; Proteins|*CH
MeSH Heading: Animal; Human; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0027-8424
Country of Publication: UNITED STATES

Record A48 from database: MEDLINE
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Title: Thermoanaerobacter brockii alcohol dehydrogenase: characterization of the active site metal and its ligand amino acids.
Author: Bogin O; Peretz M; Burstein Y
Address: Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel.
Source: Protein Sci, 1997 Feb, 6:2, 450-8
Abstract: The active-site metal ion and the associated ligand amino acids in the NADP-linked, tetrameric enzyme Thermoanaerobacter brockii alcohol dehydrogenase (TBADH) were characterized by atomic absorption spectroscopy analysis and site-directed mutagenesis. Our preliminary results indicating the presence of a catalytic zinc and the absence of a structural metal ion in TBADH (Peretz & Burstein. 1989. Biochemistry 28:6549-6555) were verified. To determine the role of the putative active-site zinc, we investigated whether exchanging the zinc for other metal ions would affect the structural and/or the enzymatic properties of the enzyme. Substituting various metal ions for zinc either enhanced or diminished enzymatic activity, as follows: Mn2+ (240%); Co2+ (130%); Cd2+ (20%); Cu2+ or V3+ (< 5%). Site-directed mutagenesis to replace any one of the three putative zinc ligands of TBADH, Cys 37, His 59, or Asp 150, with the non-chelating residue, alanine, abolished not only the metal-binding capacity of the enzyme but also its catalytic activity, without affecting the overall secondary structure of the enzyme. Replacing the three putative catalytic zinc ligands of TBADH with the respective chelating residues serine, glutamine, or cysteine damaged the zinc-binding capacity of the mutated enzyme and resulted in a loss of catalytic activity that was partially restored by adding excess zinc to the reaction. The results imply that the zinc atom in TBADH is catalytic rather than structural and verify the involvement of Cys 37, His 59, and Asp 150 of TBADH in zinc coordination.
Language of Publication: English
Unique Identifier: 97194071

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MeSH Heading (Major): Alcohol Dehydrogenase|*CH/GE/ME; Amino Acids|*ME; Bacteria, Anaerobic|*EN; Metals|*ME
MeSH Heading: Amino Acid Sequence; Animal; Binding Sites; Human; Molecular Sequence Data; Mutagenesis, Site-Directed; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0961-8368
Country of Publication: UNITED STATES

Record A49 from database: MEDLINE
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Title: Intersubunit fluorescence energy transfer in human factor VIII.
Author: Fay PJ; Smudzin TM
Address: Department of Medicine, University of Rochester School of Medicine and Dentistry, New York 14642.
Source: J Biol Chem, 1989 Aug 25, 264:24, 14005-10
Abstract: Human factor VIII circulates as a series of active heterodimers composed of a light chain (83 kDa) linked by divalent metal ion(s) to a variable sized heavy chain (93-210 kDa). Purified factor VIII subunits were modified with sulfhydryl-specific fluorophores. Probe selection was based upon the limited number of free cysteine residues in each subunit. Levels of probe incorporation suggested the presence of a single reactive cysteine residue per subunit. Amino-terminal sequence analysis of fluorescent tryptic peptides derived from the modified subunits indicated fluorophore attachment sites at Cys528 of the heavy chain (A2 domain) and Cys1858 of the light chain (A3 domain). Subunit reassociation was measured by fluorescence energy transfer using light chain modified with N-[1-pyrenyl] maleimide (fluorescence donor) and heavy chain modified with 7-diethylamino-3-[4'-maleimidophenyl]-4-methylcoumarin (fluorescence acceptor). Donor fluorescence quenching paralleled the formation of factor VIII clotting activity, and both effects were saturable with respect to added heavy chain. Based upon the degree of donor quenching, a distance of 20 A was calculated separating the two fluorophores. These results indicate a close spatial relationship between the A2 domain of heavy chain and the A3 domain of light chain in the factor VIII heterodimer.
Language of Publication: English
Unique Identifier: 89340500

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MeSH Heading (Major): Energy Transfer|*; Factor VIII|*ME
MeSH Heading: Amino Acid Sequence; Arginine|ME; Binding Sites; Cysteine|ME; Disulfides; Fluorescent Dyes; Human; Lysine|ME; Molecular Sequence Data; Spectrometry, Fluorescence; Sulfhydryl Compounds; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Disulfides); 0 (Fluorescent Dyes); 0 (Sulfhydryl Compounds); 4371-52-2 (Cysteine); 56-87-1 (Lysine); 7004-12-8 (Arginine); 9001-27-8 (Factor VIII)

Record A50 from database: MEDLINE
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Title: Quantitative investigation of copper(II) and zinc(II) complexes with S-carboxymethyl-L-cysteine and computer-simulated appraisal of their potential significance in vivo.
Author: Brumas V; Venturini M; Filella M; Berthon G
Address: Department of Chemistry, INSERM Unité 305, Université Paul Sabatier, Toulouse, France.
Source: J Inorg Biochem, 1989 Dec, 37:4, 309-23
Abstract: S-carboxymethyl-L-cysteine (SCC) is a mucolytic agent extensively used in the treatment of respiratory tract disorders. Some of the undesirable side effects observed during SCC therapy being reminiscent of symptoms characteristic of copper and zinc imbalances, the objective of this paper was to test the possible interference of SCC with the metabolism of these two metals. Copper(II)- and zinc(II)-SCC complex equilibria have thus been investigated under physiological conditions by means of classical potentiometry combined with computer-assisted calculation techniques. Formation constants derived from these studies have then been used to simulate 1) the potential influence of SCC on the distribution of the above metals in blood plasma and 2) the extent to which gastrointestinal interactions between the drug and each metal ion in turn are likely to affect the bioavailability of each other. The results of these simulations show that 1) plasma therapeutic levels of SCC are not likely to induce dramatic changes in the distributions of copper(II) and zinc(II) low molecular weight fractions, 2) the gastrointestinal distribution of the drug is not affected by standard dietary doses of these metals, and 3) in contrast, therapeutic concentrations of SCC are capable of mobilizing significant fractions of both metals into tissue-diffusible electrically neutral complexes. In conclusion significant depletions of neither copper nor zinc are to be expected from oral administration of SCC. While the drug may to some extent facilitate the excretion of Cu2+ and Zn2+ ions from blood plasma, its gastrointestinal influence is, on the contrary, favorable to a better absorption of these two metals.
Language of Publication: English
Unique Identifier: 90188350

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MeSH Heading (Major): Carbocysteine|*ME/PD/PK; Computer Simulation|*; Copper|BL/*ME; Cysteine|*AA; Zinc|BL/*ME
MeSH Heading: Absorption; Biological Availability; Gastrointestinal System|DE/ME; Human; Hydrogen-Ion Concentration; Potentiometry

Publication Type: JOURNAL ARTICLE
ISSN: 0162-0134
Country of Publication: UNITED STATES
CAS Registry/EC Number: 2387-59-9 (Carbocysteine); 4371-52-2 (Cysteine); 7440-50-8 (Copper); 7440-66-6 (Zinc)

Record A51 from database: MEDLINE
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Title: Distinct metal-thiolate clusters in the N-terminal domain of neuronal growth inhibitory factor.
Author: Faller P; Vasák M
Address: Biochemisches Institut der UniversitÂat ZÂurich, Winterthurerstrasse 190, CH-8057 ZÂurich, Switzerland.
Source: Biochemistry, 1997 Oct, 36:43, 13341-8
Abstract: Neuronal growth inhibitory factor (GIF), a brain-specific metallothionein-like protein (metallothionein-3), impairs the survival and neurite formation of cultured neurons. The metal distribution in isolated Cu4,Zn3-GIF is not known. In the present studies, the metal-thiolate clusters formed with monovalent and divalent metal ions in the N-terminal domain of human GIF [GIF(1-32)] were investigated. The cluster formation was followed by using electronic absorption, circular dichroism (CD), and magnetic circular dichroism (MCD), and in the case of Cu(I) complexes also by luminescence spectroscopy at 77 K. With Cu(I) ions, two well-defined clusters are formed involving the nine cysteine ligands of GIF(1-32), i.e., Cu4S9- and Cu6S9-clusters. In contrast to the Cu6S9-cluster, the Cu4S9-cluster shows a remarkable stability to air oxidation. As similar properties and spectral features have also been observed with isolated Cu4-5,Zn2-3-GIF, the presence of a Cu4-cluster in this GIF form is suggested. The studies with Zn(II), Cd(II), and Co(II) ions indicated the presence of a Me3S9-cluster in GIF(1-32). However, spectral features of these metal derivatives substantially differ from those reported for the corresponding Me3S9-cluster in the beta-domain of metallothioneins, suggesting structural differences. A large conformational flexibility of the Zn3- and Cd3-GIF(1-32) structures, characterized by short T2 proton relaxations, precluded their investigation by NMR methods. The significance of Cu- and Zn-clusters for the structure of biologically active GIF(1-32) is discussed.
Language of Publication: English
Unique Identifier: 98002709

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MeSH Heading (Major): Growth Inhibitors|*CH; Metals, Heavy|*CH; Nerve Tissue Proteins|*CH; Sulfhydryl Compounds|*CH
MeSH Heading: Amino Acid Sequence; Cadmium|CH; Circular Dichroism; Cobalt|CH; Comparative Study; Copper|CH; Human; Luminescence; Metallothionein|CH; Molecular Sequence Data; Nuclear Magnetic Resonance; Organometallic Compounds|CH; Protein Structure, Tertiary; Spectrophotometry; Support, Non-U.S. Gov't; Zinc|CH

Publication Type: JOURNAL ARTICLE
ISSN: 0006-2960
Country of Publication: UNITED STATES

Record A52 from database: MEDLINE
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Title: The effects of heavy metal cations and sulfhydryl reagents on degranulation from digitonin-permeabilized neutrophils.
Author: Sandborg RR; Smolen JE
Address: Department of Pediatrics, University of Michigan, Medical School, Ann Arbor 48109-0684.
Source: Biochim Biophys Acta, 1989 Mar 6, 1010:3, 330-7
Abstract: Digitonin-permeabilized neutrophils were exposed to micromolar levels of a variety of heavy metal cations and sulfhydryl oxidants to gain insight into the potential biochemical mechanisms underlying neutrophil degranulation. The results from this study suggest that the oxidation of intracellular sulfhydryl groups may play a role in neutrophil signal transduction. Evidence to support this conclusion is based on the observation that cupric phenanthroline and Cu2+/cysteine, agents reported to induce disulfide bond formation, evoke significant granule enzyme release when presented to permeabilized neutrophils. The stimulatory actions of these compounds occur in the absence of Ca2+ and are blocked by the sulfhydryl reducing agent, dithiothreitol. In addition, we observed marked potentiation of Ca2+-induced secretion by potentially physiological levels of Ni2+. Although we are unaware of any Ni2+-requiring enzymes in eukaryotic cells that are likely to be pertinent to degranulation, the ability of this divalent metal cation to lower the Ca2+ requirements for granule secretion suggests that it may play an important regulatory role in Ca2+-dependent processes. Finally, we observed significant granule release when permeabilized neutrophils were exposed to the heavy metal cations, Hg2+ and Ag+. The apparent stimulatory actions of these metals were the result of lysis rather than degranulation. Thus, the ability of these metals to lyse intracellular organelles such as lysosomal granules may contribute to their toxicological properties.
Language of Publication: English
Unique Identifier: 89150267

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MeSH Heading (Major): Metals|*PD; Neutrophils|*DE/UL; Sulfhydryl Reagents|*PD
MeSH Heading: Calcium|ME/PD; Cations|PD; Cell Membrane Permeability|DE; Copper|PD; Digitonin|PD; Dithiothreitol|PD; Glucuronidase|SE; Human; Nickel|PD; Support, U.S. Gov't, P.H.S.; Transcobalamins|SE

Publication Type: JOURNAL ARTICLE
ISSN: 0006-3002
Country of Publication: NETHERLANDS
CAS Registry/EC Number: EC 3.2.1.31 (Glucuronidase); 0 (Cations); 0 (Metals); 0 (Sulfhydryl Reagents); 0 (Transcobalamins); 11024-24-1 (Digitonin); 3483-12-3 (Dithiothreitol); 7440-02-0 (Nickel); 7440-50-8 (Copper); 7440-70-2 (Calcium)

Record A53 from database: MEDLINE
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Title: Protein carbonyl formation in blood plasma by cephalosporins.
Author: Jung Y; Chay K; Song D; Yang S; Lee M; Ahn B
Address: Department of Biochemistry, Chonnam University Medical School, Kwangju, Korea.
Source: Arch Biochem Biophys, 1997 Sep, 345:2, 311-7
Abstract: Cephalosporin antibiotics caused the formation of carbonyl groups in the plasma proteins both in vivo and in vitro. After the administration of either moxalactam (3 g/day) or cefotaxime (2 g/day) to patients for 7 days, the carbonyl contents in the plasma proteins increased markedly as determined by the 2,4-dinitrophenylhydrazine (DNPH) method. The increase in protein carbonyl groups was also visualized by the conjugation of plasma proteins with fluorescein thiosemicarbazide (FTSC) and subsequent electrophoresis. When blood plasma was incubated with cephalosporins, most of the cephalosporins tested caused the carbonyl formation in plasma proteins to significant degrees in a concentration-dependent manner. Although a number of plasma proteins and other nonplasma proteins could be modified by cephalosporins in vitro, the plasma albumin was most markedly modified in vivo as well as in vitro. The protein carbonyl formation by cephalosporins was inhibited by ascorbic acid, reduced glutathione, and cysteine, but it was not affected by FeSO4, CuSO4, desferrioxamine, EDTA, catalase, superoxide dismutase, uric acid, alpha-tocopherol, and mannitol. Sodium borohydride, when applied to moxalactam-treated plasma proteins, markedly reduced the reactivities of the protein with FTSC or DNPH, indicating that the observed reactivities of the cephalosporin-treated proteins toward FTSC or DNPH are actually due to the protein carbonyl groups. These data suggest that cephalosporins can oxidatively modify proteins in blood plasma and other tissues and that the oxidative modification of proteins may be involved in the adverse reactions observed frequently following cephalosporin therapy.
Language of Publication: English
Unique Identifier: 97452490

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MeSH Heading (Major): Blood Proteins|CH/*DE; Cephalosporins|*PD
MeSH Heading: Antioxidants|PD; Ascorbic Acid|PD; Cefotaxime|PD; Chelating Agents|PD; Comparative Study; Cysteine|PD; Glutathione|PD; Human; Metals|PD; Moxalactam|PD; Oxidation-Reduction

Publication Type: JOURNAL ARTICLE
ISSN: 0003-9861
Country of Publication: UNITED STATES

Record A54 from database: MEDLINE
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Title: Effects of sulfhydryl regents on the activity of lambda Ser/Thr phosphoprotein phosphatase and inhibition of the enzyme by zinc ion.
Author: Zhuo S; Dixon JE
Address: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, 48109-0606, USA.
Source: Protein Eng, 1998 Dec, 10:12, 1445-52
Abstract: Sulfhydryl reagents, such as dithiothreitol (DTT), affected the activity of Ser/Thr phosphoprotein phosphatases. Addition of DTT to the assay buffer increased the affinity of lambda Ser/Thr phosphoprotein phosphatase (lambda-PPase) for its Mn2+ cofactor. On the other hand, the enzyme was found to be inactivated simply by dilution in Tris buffer. The inactivation could be completely prevented by the presence of DTT or Mn2+ in the buffer. Further studies showed that oxidation or reduction of cysteine residues in lambda-PPase may not be the cause of the change in the enzyme activity. Without exception, mutation of all cysteine residues in lambda-PPase to serine did not convert the enzyme into a thiol-insensitive mutant. By careful examination of the effects of different sulfhydryl reagents, metal ion cofactors and substrates on lambda-PPase, it was found that the role of sulfhydryl reagents was the chelation of small amounts of inhibitory metal ions, which were present in plastic laboratory ware, such as disposable cuvets and tubes, with prevention of the enzyme from inactivation. One of the main contaminants found in plastic cuvets was Zn2+, which is a potent inhibitor of lambda-PPase. The inhibition of lambda-PPase by Zn2+ was characterized. Pre-treatment of the enzyme (1-4 nM) with 1 microM of ZnCl2 almost completely inhibited the enzymatic activity in response to 2 mM Mn2+. However, no significant inhibition was found when the enzyme was added to the assay mixture containing 1 microM Zn2+ and 2 mM Mn2+ . This confirms the sensitivity of the holoenzyme to inhibitory metal ions in vitro. The kinetic analysis indicated that the inhibitory metal ion might compete with Mn2+ to bind to the active site of lambda-PPase. This was further supported by the mutation of metal cofactor binding amino acid residues of the enzyme. Mutants which have less affinity for Mn2+ are also less sensitive to Zn2+. Our results suggest that inhibitory metal ions may induce a different structural conformation for lambda-PPase.
Language of Publication: English
Unique Identifier: 98202005

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MeSH Heading (Major): Enzyme Inhibitors|*PD; Phosphoprotein Phosphatase|*AI/GE/*ME; Sulfhydryl Reagents|*PD; Zinc|*PD
MeSH Heading: Animal; Binding Sites; Binding, Competitive; Cattle; Chelating Agents; Cysteine|CH; Dithiothreitol|PD; Enzyme Activation|DE; Glycerol|PD; Human; Kinetics; Manganese|ME/PD; Mutagenesis; Nitrophenols|PD; Organophosphorus Compounds|PD; Oxidation-Reduction; Serum Albumin, Bovine|PD; Tromethamine

Publication Type: JOURNAL ARTICLE
ISSN: 0269-2139
Country of Publication: ENGLAND

Record A55 from database: MEDLINE
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Title: A novel MT gene of rice plants is strongly expressed in the node portion of the stem.
Author: Yu LH; Umeda M; Liu JY; Zhao NM; Uchimiya H
Address: Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
Source: Gene, 1998 Jan, 206:1, 29-35
Abstract: We identified a cDNA encoding a metallothionein (MT)-like protein from a cDNA library of rice endosperm. This cDNA (ricMT) encoded an open reading frame of 80 amino acids, with two cysteine-rich domains at the amino-terminus and carboxy-terminus, respectively. The deduced amino acid sequence was homologous to those of class I MT-like proteins. Southern blot analysis revealed that the gene exists at one locus in the rice genome. Northern blot analysis with rice seedlings showed that the transcript level in shoots was elevated by the addition of metal ions, such as Cu, Zn, Cd, Fe, Pb and A1, whereas in roots it was reduced in the presence of metal ions other than copper. The expression level of ricMT in mature rice plants was extremely high in stems relative to leaf blades, leaf sheaths, endosperm and roots. In the first nodes, the yield of the transcript was 150-times higher than that in leaf blades. These results suggest that ricMT protein may play an important role in the metabolism of metal elements in the stem.
Language of Publication: English
Unique Identifier: 98121309

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MeSH Heading (Major): Genes, Plant|*; Metallothionein|BI/*GE; Plant Proteins|*GE; Rice|*GE
MeSH Heading: Amino Acid Sequence; Animal; Base Sequence; DNA, Plant; Gene Expression; Genome, Plant; Human; Metals; Molecular Sequence Data; Plant Stems|ME; RNA, Plant; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Tissue Distribution

Publication Type: JOURNAL ARTICLE
ISSN: 0378-1119
Country of Publication: NETHERLANDS

Record A56 from database: MEDLINE
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Title: Purification and characterization of a protease from Bacteroides gingivalis 381.
Author: Tsutsui H; Kinouchi T; Wakano Y; Ohnishi Y
Address
Source: Infect Immun, 1987 Feb, 55:2, 420-7
Abstract: An intracellular membrane-free, trypsinlike protease was isolated from cells of Bacteroides gingivalis 381. The protease was extracted from the cells by ultrasonic treatment and was purified about 250-fold with a recovery of 2% by sequential procedures. The properties of the protease were as follows: its optimal pH was 8.5; its activity was almost completely lost on incubation at 50 degrees C for 15 min; its activity was inhibited by diisopropylfluorophosphate, p-toluenesulfonyl-L-lysine chloromethyl ketone hydrochloride, leupeptin, Mn2+, Cu2+, and Zn2+; it hydrolyzed casein, azocasein, N-alpha-benzoyl-DL-arginine-p-nitroanilide (BAPNA), bovine serum albumin, azocoll, and gelatin, but not N-alpha-benzoyl-DL-lysine-p-nitroanilide or human serum immunoglobulin A; its molecular weight was estimated as 45,000 by gel filtration and 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; and its Km values for azocasein and BAPNA were 1.11% and 0.19 mM, respectively.
Language of Publication: English
Unique Identifier: 87107908

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MeSH Heading (Major): Bacteroides|*EN/GD; Peptide Hydrolases|*IP
MeSH Heading: Chromatography, DEAE-Cellulose; Cysteine|PD; Heat; Human; Hydrogen-Ion Concentration; Kinetics; Metals|PD; Molecular Weight; Periodontal Diseases|MI

Publication Type: JOURNAL ARTICLE
ISSN: 0019-9567
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.4 (Peptide Hydrolases); 0 (Metals); 4371-52-2 (Cysteine)

Record A57 from database: MEDLINE
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Title: Sensitivity of Escherichia coli (MutT) and human (MTH1) 8-oxo-dGTPases to in vitro inhibition by the carcinogenic metals, nickel(II), copper(II), cobalt(II) and cadmium(II).
Author: Porter DW; Yakushiji H; Nakabeppu Y; Sekiguchi M; Fivash MJ Jr; Kasprzak KS
Address: Laboratory of Comparative Carcinogenesis, National Cancer Institute-FCRDC, Frederick, MD 21702, USA.
Source: Carcinogenesis, 1997 Sep, 18:9, 1785-91
Abstract: The toxicity of Ni(II), Co(II) and Cu(II) in animals, and that of Cd(II) in cultured cells, has been associated with generation of the promutagenic lesion 8-oxo-7,8-dihydroguanine (8-oxoguanine) in DNA, among other effects. One possible source of this base may be 8-oxo-7,8-dihydro-2'-deoxyguanosine-5'-triphosphate (8-oxo-dGTP), a product of oxidative damage to the nucleotide pool, from which it is incorporated into DNA. To promote such incorporation, the metals would have to inhibit specific cellular 8-oxo-dGTPases that eliminate 8-oxo-dGTP from the nucleotide pool. The present study was designed to test such inhibition in vitro on 8-oxo-dGTPases from two different species, the human MTH1 protein and Escherichia coli MutT protein. In the presence of Mg(II), the natural activator of 8-oxo-dGTPases, all four metals were found to inhibit both enzymes. For MTH1, the IC50 values (+/- SE; n = 3-4) were 17 +/- 2 microM for Cu(II), 30 +/- 8 microM for Cd(II), 376 +/- 71 microM for Co(II) and 801 +/- 97 microM for Ni(II). For MutT, they were 60 +/- 6 microM for Cd(II), 102 +/- 8 microM for Cu(II), 1461 +/- 96 microM for Ni(II) and 8788 +/- 1003 microM for Co(II). Thus, Cu(II) and Cd(II) emerged as much stronger inhibitors than Ni(II) and Co(II), and MTH1 appeared to be generally more sensitive to metal inhibition than MutT. Interestingly, in the absence of Mg(II), the activity of the enzymes could be restored by Co(II) to 73% of that with Mg(II) alone for MutT, and 34% for MTH1, the other metals being much less or non-effective. The difference in sensitivity to metal inhibition between the two enzymes may reflect the differences in the amino acid ligands, especially the cysteine ligand, outside their evolutionarily conserved Mg(II)-binding active sites, which might indicate predominantly non-competitive or uncompetitive mechanism of the inhibition. The overall results suggest that inhibition of 8-oxo-dGTPases may be involved in the mechanisms of induction of the 8-oxoguanine lesion in DNA by the metal ions studied, especially the non-redox-active Cd(II) cation.
Language of Publication: English
Unique Identifier: 97466836

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MeSH Heading (Major): Bacterial Proteins|*AI; Carcinogens|*PD; Enzyme Inhibitors|*PD; Metals|*PD; Phosphoric Monoester Hydrolases|*AI
MeSH Heading: Cadmium|PD; Cobalt|PD; Copper|PD; Escherichia coli|EN; Human; Nickel|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0143-3334
Country of Publication: ENGLAND

Record A58 from database: MEDLINE
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Title: CPx-type ATPases: a class of P-type ATPases that pump heavy metals [see comments]
Author: Solioz M; Vulpe C
Address: Department of Clinical Pharmacology, University of Berne, Switzerland. solioz@ikp.unibe.ch
Source: Trends Biochem Sci, 1996 Jul, 21:7, 237-41
Abstract: ATP-driven heavy metal pumps represent a newly defined class of proteins that translocate toxic and essential metals across biological membranes. These transporters form a separate evolutionary branch of the ion-transporting P-type ATPases. We propose to call these enzymes CPx-type ATPases, based on the common novel feature of a conserved intramembranous cysteine-proline-cysteine or cysteine-proline-histidine motif.
Language of Pub
lication: English
Unique Identifier: 96334292

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MeSH Heading (Major): Adenosinetriphosphatase|CH/*ME; Conserved Sequence|*; Ion Pumps|*ME; Metals|*ME
MeSH Heading: Amino Acid Sequence; Human; Molecular Sequence Data; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0167-7640
Country of Publication: ENGLAND

Record A59 from database: MEDLINE
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Title: A mutant metallothionein which has inverse fragment composition exhibits high cadmium-binding ability.
Author: Yamaguchi R; Kurasaki M; Kojima Y
Address: Department of Environmental Medicine and Informatics, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Source: Biochem Mol Biol Int, 1997 Jan, 41:1, 49-56
Abstract: In order to investigate the role of the alpha-fragment of metallothionein (MT) in metal-binding, two mutant MTs, beta Ala alpha Cys- and alpha Cys beta Cys-mutant MTs, expressed in Escherichia coli were analyzed for their metal-binding ability. A mutant MT where all of the cysteine residues in the beta-fragment of MT were substituted by alanine residues and another mutant MT that had the inverse fragment composition (alpha-beta, i.e., beta-alpha in wild-type MT) were designated as the beta Ala alpha Cys and the alpha Cys beta Cys-mutant MT's, respectively. Both expressed Cd-binding mutant MTs were identified by amino acid analyses. From their metal-binding capacities, the two mutant MTs exhibited higher Cd-binding abilities than wild-type MT. The results suggested that the alpha-fragment plays a key role in the Cd-binding of MT, and that the metal-binding tightness of MT is dependent on the metal-binding ability of a prior fragment in MT.
Language of Publication: English
Unique Identifier: 97196544

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MeSH Heading (Major): Cadmium|*ME; Metallothionein|CH/*GE/ME
MeSH Heading: Alanine|CH; Amino Acid Sequence|PH; Binding Sites; Cysteine|CH; Escherichia coli; Human; Molecular Sequence Data; Point Mutation; Recombinant Proteins

Publication Type: JOURNAL ARTICLE
ISSN: 1039-9712
Country of Publication: AUSTRALIA

Record A60 from database: MEDLINE
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Title: Structure of the rainbow trout metallothionein B gene and characterization of its metal-responsive region.
Author: Zafarullah M; Bonham K; Gedamu L
Address: Department of Biological Sciences, University of Calgary, Alberta, Canada.
Source: Mol Cell Biol, 1988 Oct, 8:10, 4469-76
Abstract: The trout metallothionein (MT) genes consist of two members. We describe the structure of the first fish MT (tMT-B) gene which shows an overall resemblance but some remarkable differences with mammalian MT genes. The similarities included (i) tripartite structure of the gene, (ii) conservation of cysteine residues, and (iii) a TATAAA signal and two copies of metal-responsive elements (MREs). The differences consisted of (i) an AT-rich tMT-B promoter compared with highly GC-rich mammalian MT promoters and (ii) a lack of SP1-binding sites in the tMT-B promoter. Functional analysis of the tMT-B 5'-flanking region following fusion with the bacterial chloramphenicol acetyltransferase gene and its transfection into the rainbow trout hepatoma cell line revealed that sequences from positions -600 to +8 are sufficient for regulation by metals. Further deletion analyses of this fragment suggested that a minimum of 100 nucleotides upstream of the transcription initiation site are required for induction by cadmium and zinc. The tMT-B promoter was also functional in the human hepatoblastoma cell line, suggesting that an MT regulatory factor(s) is conserved in phylogenetically distant species like humans and fish.
Language of Publication: English
Unique Identifier: 89039876; GENBANK/M22487

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MeSH Heading (Major): Gene Expression Regulation|*/DE; Metallothionein|*GE; Regulatory Sequences, Nucleic Acid|*; Salmonidae|*GE; Trout|*GE
MeSH Heading: Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; Comparative Study; Evolution; Human; Metals|PD; Molecular Sequence Data; Multigene Family; Promoter Regions (Genetics); Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0270-7306
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals); 9038-94-2 (Metallothionein)

Record A61 from database: MEDLINE
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Title: Structure and tissue-specific expression of the human metallothionein IB gene.
Author: Heguy A; West A; Richards RI; Karin M
Address
Source: Mol Cell Biol, 1986 Jun, 6:6, 2149-57
Abstract: The human metallothionein (MT) IB gene (hMT-IB) is located in a region of human DNA containing at least four tandemly arranged MT genes. As deduced from its sequence, hMT-IB is likely to encode a functional protein. However, the predicted amino acid sequence differed from the hMT-I amino acid sequence in four positions. Most remarkable was the presence of an additional cysteine. Like other MT genes, hMT-IB has at least two copies of the metal-responsive element upstream from the transcription initiation site. These elements probably are responsible for the metal responsiveness of the hMT-IB promoter, leading to inducible expression of fused heterologous genes. Unlike the hMT-IIA and hMT-IA genes described previously, which are expressed in many different cell types, a high level of expression of the endogenous hMT-IB gene could be detected only in human hepatoma and renal carcinoma cell lines. Therefore, this is the first MT gene described which exhibits tissue specificity of expression. This specificity is controlled by a cis-acting mechanism involving methylation, since incubation of nonexpressing cells with an inhibitor of DNA methylation led to activation of the hMT-IB gene. In support of this notion, we found that the 5' flanking region of the hMT-IB gene was highly methylated in HeLa cells, a nonexpressing cell type, but it was not methylated in a hepatoma (expressing) cell line.
Language of Publication: English
Unique Identifier: 87064506; GENBANK/M13484; GENBANK/M13485

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MeSH Heading (Major): Metallothionein|*GE
MeSH Heading: Base Sequence; Cloning, Molecular; Gene Expression Regulation; Genes, Structural; Human; Metals; Methylation; Multigene Family; Promoter Regions (Genetics); Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.; Tissue Distribution

Publication Type: JOURNAL ARTICLE
ISSN: 0270-7306
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals); 9038-94-2 (Metallothionein)

Record A62 from database: MEDLINE
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Title: Functional constituents of the active site of human neutrophil collagenase.
Author: Mookhtiar KA; Wang F; Van Wart HE
Address
Source: Arch Biochem Biophys, 1986 May 1, 246:2, 645-9
Abstract: A series of chemical modification reactions has been carried out to identify functional constituents of the active site of human neutrophil collagenase. The enzyme is reversibly inhibited by the transition metal chelating agent 1,10-phenanthroline, and inhibition is fully reversed by zinc. Removal of weakly bound metal ions by gel filtration inactivates collagenase, and activity is fully restored on immediate readdition of calcium. The enzyme is unaffected by reagents that modify serine, cysteine, and arginine residues. However, reaction with the carboxyl reagents cyclohexylmorpholinocarbodiimide and Woodward's Reagent K lowers the activity of the enzyme substantially. Acetylimidazole inactivates the enzyme, but activity is completely restored on addition of hydroxylamine. The enzyme is also inactivated by tetranitromethane, indicating that it contains an essential tyrosine residue. Acylation of collagenase with diethyl pyrocarbonate, diketene, acetic anhydride, or trinitrobenzenesulfonate inactivates the enzyme, and activity is not restored on addition of hydroxylamine, indicating the presence of an essential lysine residue.
Language of Publication: English
Unique Identifier: 86214040

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MeSH Heading (Major): Microbial Collagenase|AI/*BL; Neutrophils|*EN
MeSH Heading: Amino Acids|BL; Binding Sites; Enzyme Reactivators; Human; Hydroxylamines|PD; Imidazoles|PD; Lysine|BL; Metals|BL; Oxyquinoline|AA/PD; Phenanthrolines|PD; Support, U.S. Gov't, P.H.S.; Tyrosine|BL; Zinc|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0003-9861
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.4.24.3 (Microbial Collagenase); 0 (Amino Acids); 0 (Enzyme Reactivators); 0 (Hydroxylamines); 0 (Imidazoles); 0 (Metals); 0 (Phenanthrolines); 148-24-3 (Oxyquinoline); 2466-76-4 (N-acetylimidazole); 55520-40-6 (Tyrosine); 56-87-1 (Lysine); 66-71-7 (1,10-phenanthroline); 7440-66-6 (Zinc); 7803-49-8 (hydroxylamine); 84-88-8 (8-hydroxyquinoline-5-sulfonic acid)

Record A63 from database: MEDLINE
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Title: Engineering a cysteine ligand into the zinc binding site of human carbonic anhydrase II.
Author: Kiefer LL; Krebs JF; Paterno SA; Fierke CA
Address: Biochemistry Department, Duke University Medical Center, Durham, North Carolina 27710.
Source: Biochemistry, 1993 Sep 28, 32:38, 9896-900
Abstract: Substitution of cysteine for threonine-199, the amino acid which hydrogen bonds with zinc-bound hydroxide in wild-type carbonic anhydrase II (CAII), leads to the formation of a new His3Cys zinc coordination polyhedron. The optical absorption spectrum of the Co(2+)-substituted threonine-199-->cysteine (T199C) variant and the three-dimensional structure [Ippolito, J. A., & Christianson, D. W. (1993) Biochemistry (following paper in this issue)] indicate that the new thiolate side chain coordinates to the metal ion, displacing the metal-bound solvent molecule. The engineered thiolate ligand increases zinc binding (4-fold) and decreases catalytic activity substantially (approximately 10(3)-fold) but not completely. However, this residual activity is due to an active species containing a zinc-bound solvent ligand with the cysteine-199 side chain occupying an alternate conformation. The equilibrium between these conformers reflects the energetic balance between the formation of the zinc-thiolate bond and structural rearrangements in the Ser-197-->Cys-206 loop necessary to achieve this metal coordination. This designed His3Cys metal polyhedron may mimic the zinc binding site in the matrix metalloproteinase prostromelysin.
Language of Publication: English
Unique Identifier: 94001999

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MeSH Heading (Major): Carbonate Dehydratase|*CH/GE/*ME; Cysteine|*; Threonine|*; Zinc|*ME
MeSH Heading: Acetazolamide|PD; Base Sequence; Binding Sites; Cobalt|ME; Human; Hydrogen Bonding; Isoenzymes|CH/GE/ME; Kinetics; Ligands; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Engineering; Recombinant Proteins|CH/ME; Spectrophotometry|MT; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0006-2960
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 4.2.1.1 (Carbonate Dehydratase); 0 (Isoenzymes); 0 (Ligands); 0 (Recombinant Proteins); 4371-52-2 (Cysteine); 59-66-5 (Acetazolamide); 72-19-5 (Threonine); 7440-48-4 (Cobalt); 7440-66-6 (Zinc)

Record A64 from database: MEDLINE
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Title: N-terminal domains of human copper-transporting adenosine triphosphatases (the Wilson's and Menkes disease proteins) bind copper selectively in vivo and in vitro with stoichiometry of one copper per metal-binding repeat.
Author: Lutsenko S; Petrukhin K; Cooper MJ; Gilliam CT; Kaplan JH
Address: Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, Oregon 97201, USA.
Source: J Biol Chem, 1997 Jul, 272:30, 18939-44
Abstract: N-terminal domains of the Wilson's and Menkes disease proteins (N-WND and N-MNK) were overexpressed in a soluble form in Escherichia coli as fusions with maltose-binding protein, purified, and their metal-binding properties were characterized. Both N-MNK and N-WND bind copper specifically as indicated by the results of metal-chelate chromatography, direct copper-binding measurements, and chemical modification of Cys residues in the presence of different heavy metals. When E. coli cells are grown in the presence of copper, N-MNK and N-WND bind copper in vivo with stoichiometry of 5-6 nmol of copper/nmol of protein. Copper released from the copper-N-MNK and copper-N-WND complexes reacts with the Cu(I)-selective chelator bicinchoninic acid in the absence of reducing agents. This suggests that in proteins, it is bound in reduced Cu(I) form, in agreement with the spectroscopic properties of the copper-bound domains. Copper bound to the domains in vivo or in vitro specifically protects the N-MNK and N-WND against labeling with the cysteine-directed probe; this indicates that Cys residues in the repetitive motifs GMTCXXCXXXIE are involved in coordination of copper. Direct involvement of the N-terminal domains in the binding of copper suggests their important role in copper-dependent functions of human copper-transporting adenosine triphosphatases (Wilson's and Menkes disease proteins).
Language of Publication: English
Unique Identifier: 97373599

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MeSH Heading (Major): Adenosinetriphosphatase|*ME; Carrier Proteins|*ME; Copper|*ME
MeSH Heading: Binding Sites; Cells, Cultured; Cysteine|ME; Hepatolenticular Degeneration|EN; Human; Kinetics; Kinky Hair Syndrome|EN; Models, Molecular; Peptide Fragments|ME; Protein Structure, Secondary; Solubility; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES

Record A65 from database: MEDLINE
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Title: Heteronuclear 113Cd-1H NMR study of metal coordination in the human retinoic acid receptor-beta DNA binding domain.
Author: Knegtel RM; Boelens R; Ganadu ML; George AV; van der Saag PT; Kaptein R
Address: Department of Chemistry, University of Utrecht, The Netherlands.
Source: Biochem Biophys Res Commun, 1993 Apr 30, 192:2, 492-8
Abstract: The two zinc fingers of the DNA binding domain of the human retinoic acid receptor-beta were labelled with 113Cd. Two- and three-dimensional heteronuclear nuclear magnetic resonance (NMR) experiments show that the first eight conserved cysteine residues coordinate the two zinc ions tetrahedrally. The ninth conserved cysteine is not involved in metal coordination. In each finger one cysteine exhibits a heteronuclear 113Cd-1H coupling constant substantially smaller than those of the other metal binding cysteines.
Language of Publication: English
Unique Identifier: 93249416

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MeSH Heading (Major): Carrier Proteins|*CH/ME; DNA|*ME; Tretinoin|*ME; Zinc|*CH
MeSH Heading: Amino Acid Sequence; Binding Sites; Cadmium; Cysteine|CH; Human; Isotopes; Molecular Sequence Data; Nuclear Magnetic Resonance; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Carrier Proteins); 0 (Isotopes); 0 (Receptors, Retinoic Acid); 302-79-4 (Tretinoin); 4371-52-2 (Cysteine); 7440-43-9 (Cadmium); 7440-66-6 (Zinc); 9007-49-2 (DNA)

Record A66 from database: MEDLINE
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Title: Air pollution particles induce IL-6 gene expression in human airway epithelial cells via NF-kappaB activation.
Author: Quay JL; Reed W; Samet J; Devlin RB
Address: National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
Source: Am J Respir Cell Mol Biol, 1998 Jul, 19:1, 98-106
Abstract: Fine particles in the air have been associated with increased mortality and morbidity. Particulate air pollution is a complex mixture which varies by region and includes a number of components including residual oil fly ash (ROFA), a byproduct of power plant and industry fuel-oil combustion. Human airway epithelial cells exposed to ROFA release inflammatory cytokines including interleukin (IL)-6, IL-8, and tumor necrosis factor. Expression of these genes is dependent upon pretranscriptional binding of cis regulatory elements, including nuclear factor kappaB (NF-kappaB). To investigate the role of NF-kappaB in the particulate-induced IL-6 response, we exposed human airway epithelial cells (BEAS-2B) to ROFA in vitro. ROFA stimulated a time- and dose-dependent increase in IL-6 messenger RNA (mRNA), which was preceded by the activation of nuclear proteins binding to the NF-kappaB sequence motif in the IL-6 promoter. Transient transfection of BEAS-2B cells with the 5' promoter region of the IL-6 gene linked to a luciferase reporter gene confirmed that NF-kappaB binding is necessary for the transcription of IL-6 mRNA. The IL-6 response was inhibited by the metal chelator deferoxamine and the free radical scavenger N-acetyl-L-cysteine, suggesting that the activation of NF-kappaB may be mediated through reactive oxygen intermediates generated by transition metals found in ROFA. Activation of NF-kappaB may therefore be a critical first step in the inflammatory cascade following exposure to particles generated by oil combustion.
Language of Publication: English
Unique Identifier: 98315034

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MeSH Heading (Major): Air Pollutants|*TO; Bronchi|CY/DE/*ME; Gene Expression Regulation|*; Interleukin-6|*GE; Metals|*TO; NF-kappa B|*ME
MeSH Heading: Acetylcysteine|PD; Carbon|TO; Cell Line; Deferoxamine|PD; DNA|ME; Epithelial Cells|CY/DE; Free Radical Scavengers|PD; Fuel Oils; Human; Promoter Regions (Genetics); RNA, Messenger|GE/ME; Transfection

Publication Type: JOURNAL ARTICLE
ISSN: 1044-1549
Country of Publication: UNITED STATES

Record A67 from database: MEDLINE
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Title: Physicochemical properties of charge isomers of recombinant human superoxide dismutase.
Author: Kajihara J; Enomoto M; Seya K; Sukenaga Y; Katoh K
Address: Pharmaceuticals Group, Nippon Kayaku Co., Ltd., Tokyo.
Source: J Biochem (Tokyo), 1988 Oct, 104:4, 638-42
Abstract: Recombinant human Cu2Zn2SOD expressed in Escherichia coli consisted of mainly three isomers with isoelectric points of 5.14 (A), 5.06 (B), and 4.99 (C). Each isomer was isolated by DEAE-Toyopearl chromatography and the physiochemical properties were investigated. No significant differences in chemical and spectrophotometric properties, such as specific activity, metal contents, amino acid composition, and UV and ESR spectra, were found. The result of labeling of free cysteine residues with ABD-F showed the disulfide bond to be formed between 57Cys and 146Cys in every isomer. A few differences were found in the CD spectrum around 260 nm and in the elution patterns on reverse-phase HPLC. The isoelectric points of the three isomers became the same after treatment by reduction and carboxymethylation and even after reduction only, pI of isomers tended to be at the value of component (A). These results suggest that the three isomers are identical in primary structure but slightly different in secondary or tertiary structure. These differences are probably derived from structural alterations around 111Cys.
Language of Publication: English
Unique Identifier: 89197872

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MeSH Heading (Major): Isoenzymes|*AN; Recombinant Proteins|*AN; Superoxide Dismutase|*AN
MeSH Heading: Amino Acids|AN; Chemistry; Comparative Study; Human; Metals|AN; Spectrum Analysis

Publication Type: JOURNAL ARTICLE
ISSN: 0021-924X
Country of Publication: JAPAN
CAS Registry/EC Number: EC 1.15.1.1 (Superoxide Dismutase); 0 (Amino Acids); 0 (Isoenzymes); 0 (Metals); 0 (Recombinant Proteins)

Record A68 from database: MEDLINE
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Title: A comparison of cysteine and serine proteinases in human gingival crevicular fluid with tissue, saliva and bacterial enzymes by analytical isoelectric focusing.
Author: Gazi MI; Cox SW; Clark DT; Eley BM
Address: Department of Periodontology, King's College School of Medicine and Dentistry, London, U.K.
Source: Arch Oral Biol, 1996 May, 41:5, 393-400
Abstract: Gingival crevicular fluid (GCF) contains several different proteinase activities and the study sought to clarify their sources. Gingival tissue and GCF were collected from chronic periodontitis patients. Gel-filtration chromatography of crude tissue extracts yielded cathepsin B and tryptase fractions sensitive to cysteine and serine proteinase inhibitors, respectively. Cell sonicates of suspected periodontal pathogens were prepared from broth cultures of reference strains. Of these, Porphyromonas gingivalis showed much the strongest activity and this had an effector response consistent with the metal-dependent cysteine proteinase described by others. Banding patterns in GCF, tissue and bacterial samples were compared on substrate-impregnated overlay membranes applied to isoelectric focusing gels. On Z-Val-Lys-Lys-Arg-AFC overlays, GCF had bands corresponding to tissue cathepsin B and the enzyme from P. gingivalis, though a contribution from Treponema denticola could not be ruled out. Use of D-Val-Leu-Arg-AFC overlays showed GCF activity similar to tissue tryptase. In GCF there were additional bands that did not correspond to any tissue or bacterial samples and on Z-Ala-Ala-Lys-AFC overlays these closely resembled activity in parotid saliva. The results confirmed that GCF contains tissue cathepsin B and tryptase, while the apparent presence of enzymes from P. gingivalis and possibly T. denticola is consistent with previous reports linking activity to these organisms. The saliva bands demonstrated that contamination of GCF may occur despite rigorous collection procedures.
Language of Publication: English
Unique Identifier: 96405161

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MeSH Heading (Major): Bacteria|*EN; Cysteine Proteinases|*AN; Gingiva|*EN; Gingival Crevicular Fluid|*EN; Saliva|*EN; Serine Proteinases|*AN
MeSH Heading: Cathepsin B|AN; Chromatography, Gel; Comparative Study; Cysteine Proteinase Inhibitors|DU; Dipeptides|DU; Human; Inflammation Mediators|AN; Isoelectric Focusing; Membranes, Artificial; Metalloproteinases|AI; Parotid Gland|EN; Periodontitis|EN/MI; Porphyromonas gingivalis|EN; Serine Proteinase Inhibitors|DU; Support, Non-U.S. Gov't; Treponema|EN

Publication Type: JOURNAL ARTICLE
ISSN: 0003-9969
Country of Publication: ENGLAND

Record A69 from database: MEDLINE
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Title: Characterization of zinc-binding sites in human stromelysin-1: stoichiometry of the catalytic domain and identification of a cysteine ligand in the proenzyme.
Author: Salowe SP; Marcy AI; Cuca GC; Smith CK; Kopka IE; Hagmann WK; Hermes JD
Address: Department of Biophysical Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065.
Source: Biochemistry, 1992 May 19, 31:19, 4535-40
Abstract: A determination of the zinc stoichiometry of the catalytic domain of the human matrix metalloproteinase stromelysin-1 has been carried out using enzyme purified from recombinant Escherichia coli that express C-terminally truncated protein. Atomic absorption spectrometry revealed that both the proenzyme (prostrom255) and the mature active form (strom255) contained nearly 2 mol of Zn/mol of protein. Full-length prostromelysin purified from a mammalian cell culture line also contained zinc in excess of 1 equiv. While zinc in prostrom255 could not be removed by dialysis against o-phenanthroline, similar treatment of mature strom255 resulted in the loss of one-half of the original zinc content. The peptidase activity of the zinc-depleted protein was reduced by greater than 85% but could be restored upon addition of Zn2+ or Co2+. Addition of a thiol-containing inhibitor to a CoZn hybrid enzyme resulted in marked spectral changes in both the visible and ultraviolet regions characteristic of sulfur ligation to Co2+. This direct evidence for an integral role in catalysis and inhibitor binding confirms the location of the exchangeable metal at the active site. To examine the environment of zinc in the proenzyme, a fully cobalt-substituted proenzyme was prepared by in vivo metal replacement. The absorbance features of dicobalt prostrom255 were consistent with metal coordination by the single cysteine present in the propeptide, although the data do not allow assignment to a particular zinc site.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication: English
Unique Identifier: 92256384

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MeSH Heading (Major): Carrier Proteins|AI/*CH/GE; Cysteine|*CH; Enzyme Precursors|*CH/GE; Metalloproteinases|AI/*CH/GE; Zinc|*CH
MeSH Heading: Amino Acid Sequence; Catalysis; Cobalt|CH; Human; Protein Binding; Recombinant Proteins|CH; Substrate Specificity

Publication Type: JOURNAL ARTICLE
ISSN: 0006-2960
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.4.24 (Metalloproteinases); EC 3.4.24.- (prostromelysin); EC 3.4.24.17 (Stromelysin 1); 0 (zinc-binding protein); 0 (Carrier Proteins); 0 (Enzyme Precursors); 0 (Recombinant Proteins); 4371-52-2 (Cysteine); 7440-48-4 (Cobalt); 7440-66-6 (Zinc)

Record A70 from database: MEDLINE
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Title: Induction of drug resistance to gold sodium thiomalate in a monocyte cell line, THP-1.
Author: Ichibangase Y; Yamamoto M; Yasuda M; Houki N; Nobunaga M
Address: Department of Clinical Immunology, Medical Institute of Bioregulation, Kyushu University, Beppu City, Oita, Japan.
Source: Clin Rheumatol, 1998, 17:3, 214-8
Abstract: The expression of metallothionein, an intracellular heavy-metal-binding protein, and p-glycoprotein, an energy-dependent drug efflux pump, was examined to study the mechanism of cell resistance to gold sodium thiomalate (GST). THP-1, one of the monocyte-derived cell lines, was cultured for 6 months and resistance to 25 microg/ml of GST (GST-resistant cells) was thus induced. The GST-resistant cells were then cultured with bucillamine to examine the presence of cross-resistance. The intracellular GST concentration was examined by flameless atomic absorption spectroscopy. The cell viability was determined by the uptake of 3-4,5 dimethylthiazole-2,5 diphenyl tetrazolium bromide (MTT). The expression of p-glycoprotein was detected by Western blotting using monoclonal anti-p-glycoprotein antibody. The expression of metallothionein was detected using the indirect immunofluorescence technique. GST-resistant cells did not show any cross-resistance to bucillamine. The rate of cytoplasmic GST accumulation decreased in the GST-resistant cells, while the rate of GST efflux also decreased. The expression of p-glycoprotein in the GST-resistant cells was not significantly different from that in the cells not treated with GST. On the other hand, the GST-resistant cells showed a higher expression of metallothionein than cells not treated with GST. These findings suggest that the induced resistance to GST might partly be due to an induction of metallothionein.
Language of Publication: English
Unique Identifier: 98357428

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MeSH Heading (Major): Gold Sodium Thiomalate|AN/*PD; Metallothionein|AN/*ME; Monocytes|CY/*DE/ME; P-Glycoprotein|AN/*DE/*ME
MeSH Heading: Anti-Inflammatory Agents, Non-Steroidal|PD; Arthritis, Rheumatoid|DT; Blotting, Western; Cell Line; Comparative Study; Cysteine|AA/PD; Cytoplasm|CH; Dose-Response Relationship, Drug; Drug Resistance; Fluorescent Antibody Technique, Indirect; Human; Sensitivity and Specificity

Publication Type: JOURNAL ARTICLE
ISSN: 0770-3198
Country of Publication: BELGIUM
CAS Registry/EC Number: 0 (Anti-Inflammatory Agents, Non-Steroidal); 0 (P-Glycoprotein); 12244-57-4 (Gold Sodium Thiomalate); 4371-52-2 (Cysteine); 65002-17-7 (bucillamine); 9038-94-2 (Metallothionein)

Record A71 from database: MEDLINE
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Title: Oxidation of low density lipoprotein by thiols: superoxide-dependent and -independent mechanisms.
Author: Heinecke JW; Kawamura M; Suzuki L; Chait A
Address: Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110.
Source: J Lipid Res, 1993 Dec, 34:12, 2051-61
Abstract: Oxidatively damaged low density lipoprotein (LDL) may cause macrophages to accumulate cholesterol in an unregulated manner, initiating the development of atherosclerotic lesions. Cultured smooth muscle cells oxidize LDL by a superoxide (O2.-)-dependent mechanism that requires L-cystine and redox-active transition metal ions in the incubation medium. To test the hypothesis that cellular reduction of L-cystine to a thiol might be involved, we exposed LDL to L-cysteine, glutathione, and D,L-homocysteine. In a cell-free system each thiol modified LDL by a pathway that required either Cu2+ or Fe3+. Thiol- and Cu(2+)-modified LDL underwent lipid peroxidation and exhibited a number of properties of cell-modified LDL, including increased mobility on agarose gel electrophoresis and fragmentation of apolipoprotein B-100. Superoxide dismutase inhibited modification of LDL by L-cysteine/Cu2+, whereas catalase and mannitol were without effect. In striking contrast, superoxide dismutase had little effect on oxidation of LDL by Cu2+ and either homocysteine or glutathione. Moreover, only L-cysteine/Cu(2+)-modified 125I-labeled LDL was degraded more rapidly than 125I-labeled LDL by human monocyte-derived macrophages: superoxide dismutase in the reaction mixture blocked the facilitated uptake of L-cysteine/Cu(2+)-modified 125I-labeled LDL, suggesting involvement of O2.-. These results indicate that LDL oxidation by L-cysteine and Cu2+ requires O2.- but not H2O2 or hydroxyl radical. The reaction may involve the metal ion-dependent formation of L-cystine radical anion which is oxidized by oxygen, yielding O2.- and the disulfide. LDL modified by L-cysteine and smooth muscle cells exhibit similar physical and biological properties, indicating that thiol-dependent generation of O2.- may be the oxidative mechanism in both systems. Thiols also promote lipid peroxidation by O2(.-)-independent reactions but human macrophages fail to rapidly degrade these oxidized LDLs.
Language of Publication: English
Unique Identifier: 94132743

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MeSH Heading (Major): Lipoproteins, LDL|*ME; Sulfhydryl Compounds|*ME; Superoxides|*PD
MeSH Heading: Cell-Free System; Cells, Cultured; Copper|PD; Cysteine|PD; Edetic Acid|PD; Fibroblasts|DE/ME; Human; Lipid Peroxidation|DE; Macrophages|DE/ME; Muscle, Smooth|DE/ME; Oleic Acids|ME; Oxidation-Reduction; Superoxide Dismutase|PD; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0022-2275
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 1.15.1.1 (Superoxide Dismutase); 0 (Lipoproteins, LDL); 0 (Oleic Acids); 0 (Sulfhydryl Compounds); 11062-77-4 (Superoxides); 112-80-1 (Oleic Acid); 4371-52-2 (Cysteine); 60-00-4 (Edetic Acid); 7440-50-8 (Copper)

Record A72 from database: MEDLINE
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Title: Alterations of thiol metabolism in human cell lines induced by low amounts of copper, mercury or cadmium ions.
Author: Hultberg B; Andersson A; Isaksson A
Address: Department of Clinical Chemistry, University Hospital, Lund, Sweden.
Source: Toxicology, 1998 Apr, 126:3, 203-12
Abstract: Ions of metals such as mercury, cadmium and copper are known to exhibit a high affinity for thiol groups and may therefore severely disturb many metabolic functions in the cell. The aim of the present study was to identify the most sensitive changes of thiol metabolism induced by the addition of low concentrations of metal ions in order to elucidate the mechanisms of metal-toxicity. The effects on thiol metabolism by copper ions seemed to differ from that of mercury and cadmium ions. Copper ions exhibited mainly two effects that were different from those of mercury and cadmium ions. They lowered the reduced fractions of thiols and increased the release of homocysteine into the medium, whereas mercury and cadmium ions mainly influenced the metabolism of glutathione by increasing its synthesis. Even 0.1 micromol/l of copper ions increased the release of homocysteine in HeLa cell lines. An increased cellular concentration of glutathione and an increased release of glutathione into the medium were observed after addition of mercury and cadmium ions at a concentration of 1 micromol/l, which is just above the toxicity limit in human blood. The different cell lines varied in some respects in their response to the addition of metal ions. Cadmium ions had no effect on thiol metabolism in endothelial cell lines, and copper ions did not significantly increase the release of homocysteine into the medium in hepatoma cell lines. Furthermore, the metabolism of thiols during basal conditions (without the addition of metal ions) differed somewhat in the three cell lines investigated. One example is the low amount of extracellular glutathione in hepatoma cell lines, which probably was due to its rapid degradation to cysteinylglycine by gamma-glutamyl-transpeptidase.
Language of Publication: English
Unique Identifier: 98337725

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MeSH Heading (Major): Cadmium|*TO; Copper|*TO; Cysteine|*ME; Glutathione|*ME; Homocysteine|*ME; Mercury|*TO
MeSH Heading: gamma-Glutamyltransferase|ME; Carcinoma, Hepatocellular; Cell Line; Culture Media|AN; Dipeptides|ME; Endothelium; Hela Cells; Human; Support, Non-U.S. Gov't; Tumor Cells, Cultured

Publication Type: JOURNAL ARTICLE
ISSN: 0300-483X
Country of Publication: IRELAND

Record A73 from database: MEDLINE
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Title: Identification and functional requirement of Cu(I) and its ligands within coagulation factor VIII.
Author: Tagliavacca L; Moon N; Dunham WR; Kaufman RJ
Address: Department of Biological Chemistry, Ann Arbor, Michigan 48109, USA.
Source: J Biol Chem, 1997 Oct, 272:43, 27428-34
Abstract: Coagulation factor VIII (FVIII) is a heterodimer consisting of a light chain of 80 kDa (domains A3-C1-C2) in a metal ion-dependent association with a 220-kDa heavy chain (domains A1-A2-B). The nature of the metal ion-dependent association between the heavy and light chains was investigated using atomic absorption spectroscopy, electron paramagnetic resonance spectroscopy (EPR), and site-directed mutagenesis and expression of the FVIII cDNA. Whereas copper ion was not detected in intact recombinant FVIII, EDTA dissociation of the chains yielded an EPR signal consistent with 1 mol of Cu(I)/mol of active protein, supporting the hypothesis that a single molecule of reduced copper ion is buried within intact FVIII and is released and oxidized upon treatment with EDTA. Cu(I), and not Cu(II), was able to reconstitute FVIII activity from dissociated chains, demonstrating a requirement for Cu(I) in FVIII function. Three potential copper ion binding sites exist within FVIII: one type-2 site and two type-1 sites. The importance of these potential copper ion ligands was tested by studying the effect of site-directed mutants. Of the two histidines that compose the type-2 binding site, the His-1957 --> Ala mutant displayed secretion, light and heavy chain assembly, and activity similar to wild-type FVIII, while mutant His-99 --> Ala was partially defective for secretion and had low levels of heavy and light chain association and activity. In contrast, FVIII having the mutation Cys-310 --> Ser within the type-1 copper binding site in the A1 domain was inactive and partially defective for secretion from the cell, and the heavy and light chains of the secreted protein were not associated. Mutant Cys-2000 --> Ser within the A3 domain displayed secretion, assembly, and activity similar to that for wild-type FVIII. These results support the hypothesis that Cu(I) is buried within the type-1 copper binding site within the A1 domain and is required for FVIII chain association and activity.
Language of Publication: English
Unique Identifier: 98001730

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MeSH Heading (Major): Copper|*ME; Factor VIII|BI/*CH/*ME
MeSH Heading: Amino Acid Substitution; Animal; Binding Sites; Culture Media, Conditioned; Cysteine Proteinase Inhibitors|PD; CHO Cells; COS Cells; Electron Spin Resonance Spectroscopy; Hamsters; Human; Kinetics; Leupeptins|PD; Ligands; Macromolecular Systems; Mutagenesis, Site-Directed; Recombinant Proteins|BI/CH/ME; Spectrophotometry, Atomic Absorption; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0021-9258
Country of Publication: UNITED STATES

Record A74 from database: MEDLINE
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Title: Metallothionein induction in human peripheral blood lymphocytes by heavy metals.
Author: Yamada H; Koizumi S
Address: Department of Experimental Toxicology, National Institute of Industrial Health, Kawasaki, Japan.
Source: Chem Biol Interact, 1991, 78:3, 347-54
Abstract: Human peripheral blood lymphocytes have the capacity to produce metallothioneins (MTs) as a protective response to cadmium exposure. To define the range of metal species inducing lymphocyte MTs, cellular proteins synthesized after exposure to each of 11 heavy metals were analyzed by gel electrophoresis. Toxic metals such as cadmium, mercury and silver were found to induce thioneins (apoproteins of MTs) at relatively low concentrations (maximum at approximately 10 microM), whereas less toxic metals such as zinc, copper and nickel were inductive at relatively high concentrations (maximum at approximately 200 microM). Tin, lead, iron, cobalt, and manganese did not induce thioneins. The heavy metal specificity of MT induction in the lymphocyte resembles that in the liver, and the regulatory mechanism of MT production seems to be similar in both of these tissues. In the cells exposed to highly toxic metals such as cadmium and mercury, expression of cytotoxicity (represented by decline of cysteine uptake) was remarkable at the metal concentrations higher than those saturating thionein induction, supporting the protective role of MTs against heavy metals.
Language of Publication: English
Unique Identifier: 91300580

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MeSH Heading (Major): Lymphocytes|DE/*ME; Metallothionein|*BI; Metals|*TO
MeSH Heading: Electrophoresis, Polyacrylamide Gel; Human; Male

Publication Type: JOURNAL ARTICLE
ISSN: 0009-2797
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 0 (Metals); 9038-94-2 (Metallothionein)

Record A75 from database: MEDLINE
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Title: Characterization of a 105-kDa polypeptide encoded in gene 1 of the human coronavirus HCV 229E.
Author: Grötzinger C; Heusipp G; Ziebuhr J; Harms U; Süss J; Siddell SG
Address: Department of Viral Zoonoses, Federal Institute for Health Protection of Consumers and Veterinary Medicine, Berlin, Germany.
Source: Virology, 1996 Aug, 222:1, 227-35
Abstract: Gene 1 of the human coronavirus HCV 229E encompasses approximately 20.7 kb and contains two overlapping open reading frames, ORF 1a and ORF 1b. The downstream ORF 1b is expressed by a mechanism involving (-1) ribosomal frameshifting. Translation of mRNA 1, which is thought to be equivalent to the viral genomic RNA, results in the synthesis of two large polyproteins, pp1a and pp1ab. These polyproteins contain motifs characteristic of papain-like and 3C-like proteinases, RNA-dependent RNA polymerases, helicases, and metal-binding proteins. In this study, we have produced pp1ab-specific monoclonal antibodies and have used them to detect an intracellular, 105-kDa viral polypeptide that contains the putative RNA polymerase domain. Furthermore, using trans cleavage assays with bacterially expressed HCV 229E 3C-like proteinase, we have demonstrated that the 105-kDa polypeptide is released from pp1ab by cleavage at the dipeptide bonds Gln-4068/Ser-4069 and Gln-4995/Ala-4996. These data contribute to the characterization of coronavirus 3C-like proteinase-mediated processing of pp1ab and provide the first identification of an HCV 229E ORF 1ab-encoded polypeptide in virus-infected cells.
Language of Publication: English
Unique Identifier: 96400126

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MeSH Heading (Major): Coronavirus, Human|EN/*GE/ME; Peptides|GE/IM/*ME; Viral Proteins|GE/*ME
MeSH Heading: Animal; Antibodies, Monoclonal|IM; Cell Line; Cysteine Proteinases|GE/ME; Female; Hela Cells; Human; Mice; Mice, Inbred BALB C; Protein Processing, Post-Translational; Recombinant Fusion Proteins|ME; RNA Replicase|GE/ME; Substrate Specificity; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0042-6822
Country of Publication: UNITED STATES

Record A76 from database: MEDLINE
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Title: Metal binding properties and secondary structure of the zinc-binding domain of Nup475.
Author: Worthington MT; Amann BT; Nathans D; Berg JM
Address: Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Source: Proc Natl Acad Sci U S A, 1996 Nov, 93:24, 13754-9
Abstract: Nup475 is a nuclear zinc-binding protein of unknown function that is induced in mammalian cells by growth factor mitogens. Nup475 contains two tandemly repeated sequences YKTELCX8CX5CX3H (Cys3His repeats) that are thought to be zinc-bindin domains. Similar sequences have been found in a number of proteins from various species of eukaryotes. To determine the metal binding properties and secondary structure of the putative zinc-binding domains of Nup475, we have used synthetic or recombinant peptides that contain one or two domain sequences. The peptide with a single domain bound 1.0 +/- 0.1 equivalents of Co2+, and the peptide with two domains bound 1.7 +/- 0.4 equivalents of Co2+. Both peptides bound Co2+ and Zn2+ with affinities similar to those of classical zinc finger peptides. In each case, the Co2+ complex exhibited strong d-d transitions characteristic of tetrahedral coordination. For structural studies by nuclear magnetic resonance spectroscopy, we used a more soluble two-domain peptide that had a single amino acid substitution in a nonconserved amino acid residue in the second Cys3His repeat. The mutant peptide unexpectedly showed loss of one of its metal binding sites and displayed ordered structure for only the first Cys3His sequence. On the basis of the nuclear magnetic resonance data, we propose a structure for the Nup475 metal-binding domain in which the zinc ion is coordinated by the conserved cysteines and histidine, and the conserved YKTEL motif forms a parallel sheet-like structure with the C terminus of this domain. This structure is unlike that of any previously described class of metal binding domain.
Language of Publication: English
Unique Identifier: 97098467

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MeSH Heading (Major): Protein Structure, Secondary|*; Proteins|*CH/IP/*ME; Zinc|*ME
MeSH Heading: Amino Acid Sequence; Animal; Binding Sites; Chromatography, High Pressure Liquid; Cloning, Molecular; Cobalt|ME; Cysteine; Escherichia coli; Histidine; Human; Mammals; Models, Structural; Molecular Sequence Data; Nuclear Magnetic Resonance; Peptide Fragments|CH/CS; Recombinant Proteins|CH/IP/ME; Sequence Homology, Amino Acid; Spectrophotometry; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0027-8424
Country of Publication: UNITED STATES

Record A77 from database: MEDLINE
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Title: Cloning and nucleotide sequence of a complementary DNA encoding Xenopus laevis metallothionein: mRNA accumulation in response to heavy metals.
Author: Saint-Jacques E; Séguin C
Address: Centre de recherche en cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, Canada.
Source: DNA Cell Biol, 1993 May, 12:4, 329-40
Abstract: A cDNA encoding Xenopus laevis metallothionein (MT) was cloned from a cDNA library constructed using liver poly(A+)RNA of X. laevis adult males treated with CdCl2. The probe used to screen the library was a MT-specific DNA fragment obtained by means of the polymerase chain reaction (PCR) and degenerate oligodeoxynucleotide primers. The cDNA clone encodes a putative protein of 62 amino acids, of which 20 are cysteine residues. The position of all the cysteine residues is conserved with respect to mammalian MT sequences. The amino acid sequence of this X. laevis MT, designated XIMT-A, shares between 60% and 67% identity with various vertebrate MTs. Overall, the structure of XIMT-A is no similar in sequence to MT-1 than it is to MT-2 isoforms of various vertebrates. Ten different X. laevis MT cDNA isolates were partially sequenced and turned out to be identical, suggesting a single species of MT mRNA. Southern blot analysis of X. laevis DNA reveals that the XlMT-A gene is present in at least two copies. This result is consistent with the suggestion that a genome duplication occurred in a X. laevis ancestor. The in vivo response to increasing doses of Cd2+, Zn2+, and Cu2+ metal salts was tested. In the liver, all three metals proved to be potent inducers, raising MT mRNA levels between 50- and 100-fold. The maximum response to Cd2+ was at 12 hr after injection and to Zn2+ at 24 hr after injection. High levels of mRNA were maintained for more than 48 hr. Cd2+ and Zn2+ induced XlMT-A mRNA in all tissues examined (kidney, spleen, heart, intestine, testes, and brain). Dexamethasone did not induce MT mRNA synthesis in the liver.
Language of Publication: English
Unique Identifier: 93263990; GENBANK/M96729

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MeSH Heading (Major): Metallothionein|*GE; Metals|*PD; RNA, Messenger|*ME
MeSH Heading: Amino Acid Sequence; Animal; Base Sequence; Blotting, Southern; Cloning, Molecular; DNA; Human; Kidney|ME; Liver|ME; Male; Molecular Sequence Data; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't; Xenopus laevis

Publication Type: JOURNAL ARTICLE
ISSN: 1044-5498
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Metals); 0 (RNA, Messenger); 9007-49-2 (DNA); 9038-94-2 (Metallothionein)

Record A78 from database: MEDLINE
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Title: The peptidase activity of human serum butyrylcholinesterase: studies using monoclonal antibodies and characterization of the peptidase.
Author: Rao RV; Balasubramanian AS
Address: Department of Neurological Sciences, Christian Medical College and Hospital Vellore, India.
Source: J Protein Chem, 1993 Feb, 12:1, 103-10
Abstract: Purified human serum butyrylcholinesterase, which exhibits cholinesterase, aryl acylamidase, and peptidase activities, was cross-reacted with two different monoclonal antibodies raised against human serum butyrylcholinesterase. All three activities were immunoprecipitable at different dilutions of the two monoclonal antibodies. At the highest concentration of the antibodies used, nearly 100% of all three activities were precipitated, and could be recovered to 90-95% in the immunoprecipitate. The peptidase activity exhibited by the purified butyrylcholinesterase was further characterized using both Phe-Leu and Leu-enkephalin as substrates. The pH optimum of the peptidase was in the range of 7.5-9.5 and the divalent cations Co2+, Mn2+, and Zn2+ stimulated its activity. EDTA and other metal complexing agents inhibited its activity. Thiol agents and -SH group modifiers had no effect. The serine protease inhibitors, diisopropylfluorophosphate and phenyl methyl sulfonyl fluoride, did not inhibit. When histidine residues in the enzyme were modified by diethylpyrocarbonate, the peptidase activity was not affected, but the stimulatory effect of Co2+, Mn2+, and Zn2+ disappeared, suggesting the involvement of histidine residues in metal ion binding. These general characteristics of the peptidase activity were also exhibited by a 50 kD fragment obtained by limited alpha-chymotrypsin digestion of purified butyrylcholinesterase. Under all assay conditions, the peptidase released the two amino acids, leucine and phenylalanine, from the carboxy terminus of Leu-enkephalin as verified by paper chromatography and HPLC analysis. The results suggested that the peptidase behaved like a serine, cysteine, thiol-independent metallopeptidase.
Language of Publication: English
Unique Identifier: 93151960

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MeSH Heading (Major): Butyrylcholinesterase|*BL/IM; Peptide Peptidohydrolases|*BL
MeSH Heading: Amidohydrolases|ME; Amino Acid Sequence; Antibodies, Monoclonal|IM; Chelating Agents|PD; Cholinesterases|ME; Chromatography, High Pressure Liquid; Cross Reactions; Enkephalin, Leucine|CH; Enzyme Activation; Histidine|CH; Human; Metals|CH; Molecular Sequence Data; Precipitin Tests; Protease Inhibitors|PD; Sulfhydryl Compounds|CH/PD; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0277-8033
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.1.1.- (Butyrylcholinesterase); EC 3.1.1.8 (Cholinesterases); EC 3.4.- (Peptide Peptidohydrolases); EC 3.5. (Amidohydrolases); EC 3.5.1.13 (aryl acylamidase); 0 (Antibodies, Monoclonal); 0 (Chelating Agents); 0 (Metals); 0 (Protease Inhibitors); 0 (Sulfhydryl Compounds); 58822-25-6 (Enkephalin, Leucine); 7006-35-1 (Histidine)

Record A79 from database: MEDLINE
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Title: Disruption of prosomes by some bivalent metal ions results in the loss of their multicatalytic proteinase activity and cancels the nuclease resistance of prosomal RNA.
Author: Nothwang HG; Coux O; Bey F; Scherrer K
Address: Institut Jacques Monod, Université Paris, France.
Source: Biochem J, 1992 Nov 1, 287 ( Pt 3):, 733-9
Abstract: Prosomes are ribonucleoprotein particles constituted by a variable set of about 20 proteins found associated with untranslated mRNA. In addition, they contain a small RNA, the presence of which has been an issue of controversy for a long time. The intact particles have a multicatalytic proteinase (MCP) activity and are very stable; we have never observed autodigestion of the particle by its intrinsic proteinase activity. Surprisingly it was found that Zn2+ and Cu2+ ions at concentrations of 0.1-1 mM disrupt the prosome particles isolated from HeLa cells and duck erythroblasts and abolish instantaneously its MCP activity, without altering the two-dimensional electrophoretic pattern of the constituent proteins. Fe2+, however, seems to induce autodegradation rather than dissociation of the prosome constituents. Most interestingly, protein or oligopeptide substrates protect the particle and its proteinase activity from disruption by Zn2+ or Cu2+. Nuclease-digestion assays reveal that the prosomal RNA, which is largely resistant in the intact particle, becomes digestible after dissociation of prosomes by Zn2+. These data give, for the first time, unambiguous proof of the presence of an RNA in the particle. Furthermore, they demonstrate a structure-function relationship between the complex and its enzyme activity, which seems to be based on the particle as an entity and not on the single constituent proteins.
Language of Publication: English
Unique Identifier: 93075024

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MeSH Heading (Major): Cysteine Proteinases|*ME; Metals|*PD; Multienzyme Complexes|*ME; Ribonucleoproteins|*ME; RNA, Messenger|*ME
MeSH Heading: Animal; Calcium|PD; Cations, Divalent; Copper|PD; Ducks; Electrophoresis, Polyacrylamide Gel; Ferrous Compounds|PD; Hela Cells; Human; Kinetics; Magnesium|PD; Ribonucleases|ME; Species Specificity; Substrate Specificity; Support, Non-U.S. Gov't; Zinc|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0264-6021
Country of Publication: ENGLAND
CAS Registry/EC Number: EC 3.1.- (Ribonucleases); EC 3.4.22 (Cysteine Proteinases); EC 3.4.99.46 (multicatalytic endopeptidase complex); 0 (Cations, Divalent); 0 (Ferrous Compounds); 0 (Metals); 0 (Multienzyme Complexes); 0 (Ribonucleoproteins); 0 (RNA, Messenger); 7439-95-4 (Magnesium); 7440-50-8 (Copper); 7440-66-6 (Zinc); 7440-70-2 (Calcium)

Record A80 from database: MEDLINE
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Title: Transient induction of the MRP/GS-X pump and gamma-glutamylcysteine synthetase by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea in human glioma cells.
Author: Gomi A; Shinoda S; Masuzawa T; Ishikawa T; Kuo MT
Address: Department of Molecular Pathology, The University of Texas, M. D. Anderson Cancer Center, Houston 77030, USA.
Source: Cancer Res, 1997 Dec, 57:23, 5292-9
Abstract: Treatment of human glioma A172 cells with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), an alkylating antitumor agent the primary target of which has been thought to be DNA, resulted in elevated expression of mRNA for multidrug resistance-associated protein (MRP) within the first 2 h and then a decrease in expression 24 h after the treatment. Western blot analyses revealed that levels of MRP in these ACNU-treated cells paralleled mRNA levels. Membrane vesicles prepared from ACNU-treated cells also displayed elevated transport activities for leukotriene C4, a known substrate for MRP. Gamma-glutamylcysteine synthetase (gamma-GCS) mRNA expression was coinduced with MRP by ACNU. Because gamma-GCS is the rate-limiting enzyme involved in the de novo biosynthesis of glutathione, increases in glutathione were also transiently induced by ACNU. These results demonstrate for the first time that the expression of functional MRP and gamma-GCS can be transiently coinduced by ACNU. Multiple short exposures (1 h) of ACNU following a long duration (1 week) of drug-free conditions resulted in the development of an ACNU-resistant population (designated A172R) that overexpressed MRP/gamma-GCS mRNA and had elevated transport activities for leukotriene C4. A172R exhibited cross-resistance to the antitumor drug doxorubicin and heavy metal sodium arsenate but not to cisplatin. Our results also demonstrate that intermittent treatments of human glioma cells with ACNU can lead to the development of MRP-related multidrug resistance. These results, taken together, reveal a possible new mechanism of the development of drug resistance for the antitumor nitrosoureas.
Language of Publication: English
Unique Identifier: 98053901

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MeSH Heading (Major): Antineoplastic Agents|*PD; ABC Transporters|AN/*BI; Carrier Proteins|AN/*BI; Gene Expression Regulation, Neoplastic|*DE; Glioma|*ME; Glutamate-Cysteine Ligase|AN/*BI; Nimustine|*PD; Transcription, Genetic|*DE
MeSH Heading: Amino Acid Sequence; Animal; Antibodies; Arsenates|TO; Biological Transport; Cisplatin|TO; Doxorubicin|TO; Drug Resistance, Multiple; Enzyme Induction; Glutathione|ME; Human; Leukotriene C4|ME; Mice; Mice, Inbred BALB C; Models, Biological; Molecular Sequence Data; Peptide Fragments|CH/IM; RNA, Messenger|BI; Support, U.S. Gov't, P.H.S.; Tumor Cells, Cultured

Publication Type: JOURNAL ARTICLE
ISSN: 0008-5472
Country of Publication: UNITED STATES

Record A81 from database: MEDLINE
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Title: Complexation of copper(I) by thioamino acids. Implications for copper speciation in blood plasma.
Author: Tran Ho LC; May PM; Hefter GT
Address: Division of Science, Murdoch University, Australia.
Source: J Inorg Biochem, 1997 Nov, 68:3, 225-31
Abstract: There is mounting evidence that Cu(I) is the most important oxidation state of copper in many physiological systems. Research into Cu(I)-thioamino acid complex formation serves not only to improve the chelation therapy for treating copper intoxication but may also provide a better understanding of many facets of normal copper metabolism. Formation constants for the ternary mixed ligand complexes of Cu(I) with cysteine (Cys), glutathione (GSH) and penicillamine (Pen) are reported here for the first time. Potentiometric titrations, using techniques specially developed for the stabilization of aqueous Cu(I), were performed at 25 degrees C in 1.00 M (Na)Cl. It was found that precipitation severely limits the experimentally accessible pH range and, consequently, the computer analysis of the binary metal-ligand systems; however, it is also found that this is less of a problem when two different ligands are present. This latter fact permitted better models of the binary systems to be developed. The formation constants of Cu(I)-thioamino acids determined in this work were used in an improved computer simulation of copper speciation in blood plasma which, for the first time, incorporates redox equilibria.
Language of Publication: English
Unique Identifier: 98013970

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MeSH Heading (Major): Copper|*BL/ME; Thioamides|*BL
MeSH Heading: Computer Simulation; Cysteine|BL; Databases, Factual; Glutathione|BL; Human; Hydrogen-Ion Concentration; Ligands; Models, Biological; Oxidation-Reduction; Penicillamine|BL; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0162-0134
Country of Publication: UNITED STATES

Record A82 from database: MEDLINE
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Title: Human papillomavirus type 16 E6 proteins with glycine substitution for cysteine in the metal-binding motif.
Author: Kanda T; Watanabe S; Zanma S; Sato H; Furuno A; Yoshiike K
Address: Department of Enteroviruses, National Institute of Health, Tokyo, Japan.
Source: Virology, 1991 Dec, 185:2, 536-43
Abstract: The human papillomavirus type 16 (HPV 16) E6 is a 151 amino acid protein containing four metal-binding motifs, Cys-X-X-Cys. We constructed and characterized three mutants with Gly substitutions for Cys within the motif; for Cys-66, for Cys-136, and for both, respectively. Zinc binding to bacterially expressed E6 was markedly reduced by the substitution for Cys-66, but DNA binding was unaffected by any of these mutations. Immunofluorescence staining showed that, whereas the E6 expressed in monkey COS-1 cells appeared mostly nuclear, the Cys-66 mutant appeared cytoplasmic. Subcellular fractionation followed by immunoprecipitation showed that the E6 in COS-1 cells was located in the membrane, nuclear, and nuclear-wash fractions, but not in the soluble cytoplasmic fraction, and that the nuclear Cys-66 protein was markedly reduced. The mutant proteins in COS-1 cells appeared to be less stable than the wild type, because the immunofluorescent cells were fewer and because the E6 bands in autoradiograms were less dense. The substitution mutants lost their capacity to enhance HPV 16 E7 transformation of rat 3Y1 cells. The data indicate that Cys-66 plays a crucial role for zinc binding and nuclear localization of E6 and that both Cys-66 and Cys-136 are required for a stable or functional structure of E6.
Language of Publication: English
Unique Identifier: 92074216

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MeSH Heading (Major): Oncogene Proteins, Viral|CH/GE/ME/*PH; Papillomavirus|GE/*PH; Zinc|*ME; Zinc Fingers|*PH
MeSH Heading: Amino Acid Sequence; Animal; Antibodies, Monoclonal; Cell Line; Cell Transformation, Viral|GE; Cysteine|ME; DNA|ME; DNA Mutational Analysis; Fluorescent Antibody Technique; Glycine|ME; Haplorhini; Human; Molecular Sequence Data; Plasmids|GE; Precipitin Tests; Rats; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0042-6822
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (oncogene protein E6, human papillomavirus type 16); 0 (Antibodies, Monoclonal); 0 (Oncogene Proteins, Viral); 0 (Plasmids); 4371-52-2 (Cysteine); 56-40-6 (Glycine); 7440-66-6 (Zinc); 9007-49-2 (DNA)

Record A83 from database: MEDLINE
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Title: Monoclonal antibodies specific for Semliki Forest virus replicase protein nsP2.
Author: Kujala P; Rikkonen M; Ahola T; Kelve M; Saarma M; Kääriäinen L
Address: Biocentre Viikki, Institute of Biotechnology, University of Helsinki, Finland. ptkujala@operoni.helsinki.fi
Source: J Gen Virol, 1997 Feb, 78 ( Pt 2):, 343-51
Abstract: A panel of monoclonal antibodies (MAbs) was raised against Semliki Forest virus (SFV) nonstructural protein nsP2, which is a protease, an NTPase, a putative RNA helicase, and a regulator of the synthesis of the subgenomic 26S mRNA encoding the structural proteins. nsP2, used for immunization, was expressed as a histidine fusion protein in Escherichia coli and purified by metal affinity chromatography. Dot-blot assay, using a membrane fraction from SFV-infected cells as antigen, gave 33 positive clones. Of these, 30 MAbs recognized nsP2 in Western immunoblotting, and 25 showed positive indirect immunofluorescence (IFAT) in SFV-infected cells; 15 MAbs stained the cytoplasmic vacuoles (CPVI), which are the sites of viral RNA synthesis in alphavirus-infected cells. MAb 3B5 recognized only CPVIs, as shown by double immunofluorescence staining with polyclonal anti-nsP3 antiserum. Most of the MAbs (20/33) recognized the nuclear form of nsP2, which may be associated with SFV neurovirulence. Immunoprecipitation with MAbs revealed that the SFV nonstructural proteins are associated with each other. None of the MAbs recognized Sindbis virus nsP2 in immunoblotting, indicating that they were directed to non-conserved sequences specific for SFV. Interestingly, these epitopes were located mostly within the N-terminal half of nsP2. Unexpectedly, the anti-nsP2 MAb 1E9 cross-reacted strongly with a host protein of 78 kDa from uninfected human, murine, avian and insect cells. This protein was identified as the immunoglobulin binding protein, BiP, by 2-D gel mapping and reaction with anti-BiP antiserum.
Language of Publication: English
Unique Identifier: 97170752

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MeSH Heading (Major): Antibodies, Monoclonal|*IM; Antibodies, Viral|*IM; Cysteine Proteinases|GE/*IM; Semliki Forest Virus|EN/GE/*IM
MeSH Heading: Animal; Antibody Specificity; Cell Line; Escherichia coli; Hamsters; Human; Hybridomas; Mice; Precipitin Tests; Recombinant Fusion Proteins|GE/IM; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0022-1317
Country of Publication: ENGLAND

Record A84 from database: MEDLINE
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Title: Determination and metabolism of dithiol chelating agents. XVII. In humans, sodium 2,3-dimercapto-1-propanesulfonate is bound to plasma albumin via mixed disulfide formation and is found in the urine as cyclic polymeric disulfides.
Author: Maiorino RM; Xu ZF; Aposhian HV
Address: Department of Molecular and Cellular Biology, University of Arizona, Tucson, USA.
Source: J Pharmacol Exp Ther, 1996 Apr, 277:1, 375-84
Abstract: The binding of 2,3-dimercapto-1-propanesulfonate (DMPS) in plasma was determined in three healthy young adults after a single 300-mg p.o. dose. By 5 hr after DMPS administration, 62.5% of the total plasma DMPS was bound to proteins. The remainder consisted of nonprotein associated DMPS disulfides (36.6%) and unaltered DMPS (0.9%). Protein-bound DMPS consisted of a DMPS-albumin complex (84%) and a higher molecular weight protein complex (16%), perhaps albumin aggregates. DMPS was released from the isolated DMPS-albumin complex after treatment with dithiothreitol, indicating that it was bound via a disulfide linkage. The half-life of unaltered DMPS was 1.8 hr, whereas that of altered DMPS was 20 hr, suggesting that the DMPS-albumin disulfide complex is stable and that DMPS was released from it slowly. In addition, the biotransformation of OMPS to disulfide forms was extensive. By 9 hr after administration, 10% of the total urinary DMPS was unchanged drug and 90% was altered DMPS. The latter was converted to DMPS by dithiothreitol, indicating that the altered DMPS consisted of disulfides. In 2- to 4-hr urine, DMPS disulfides included cyclic polymeric DMPS disulfides (97%), DMPS-cysteine (1:2) mixed disulfide (2.5%) and acyclic DMPS disulfide (0.5%). The cyclic polymeric DMPS disulfides were present in a major (91.5%) and minor (5.5%) form. DMPS-albumin mixed disulfide and nonprotein DMPS disulfides may prolong the heavy metal mobilizing activity of DMPS and thus may represent reservoirs of DMPS which can be released by disulfide reduction in vivo.
Language of Publication: English
Unique Identifier: 96185099

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MeSH Heading (Major): Chelating Agents|*ME; Disulfides|*ME; Serum Albumin|*ME; Unithiol|*ME
MeSH Heading: Adult; Captopril|ME; Chromatography, Thin Layer; Cysteine|ME; Dithiothreitol|PD; Human; Male; Penicillamine|ME; Protein Binding; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0022-3565
Country of Publication: UNITED STATES

Record A85 from database: MEDLINE
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Title: Physiological thiol compounds exert pro- and anti-oxidant effects, respectively, on iron- and copper-dependent oxidation of human low-density lipoprotein.
Author: Lynch SM; Frei B
Address: Whitaker Cardiovascular Institute, Boston University School of Medicine, MA 02118, USA.
Source: Biochim Biophys Acta, 1997 Apr, 1345:2, 215-21
Abstract: The effects of thiol compounds on oxidation of human low-density lipoprotein (LDL, 0.2 mg of protein/ml) by Cu2+ or Fe3+ (10 microM, each) were investigated in an in vitro system. L-Cysteine (CYS, 25 microM-1 mM) inhibited Cu2+-dependent, but facilitated Fe3+-dependent, oxidation of LDL in a dose-dependent manner. D,L-Homocysteine (HCY, 1 mM) and glutathione (GSH, 1 mM) similarly inhibited Cu2+-dependent, while facilitating Fe3+-dependent, oxidation of LDL. However, the effectiveness of these thiols (CYS, HCY, and GSH; 1 mM each) at mediating either Cu(2+)- or Fe3+-dependent LDL oxidation was not equivalent. Thus, Cu2+-dependent oxidation of LDL was most effectively inhibited by GSH, an intermediate effect was observed with HCY, and CYS was least effective. In contrast, a reversal of this pattern was observed for facilitation of Fe3+-dependent oxidation of LDL, with CYS being most effective and GSH being least effective. Interestingly, although the disulfides cystine and homocystine (0.5 mM, each) were without effect on either Cu(2+)- or Fe3+-dependent LDL oxidation, both glutathione disulfide (GSSG, 0.5 mM) and methionine (1 mM), an S-methylated derivative of HCY, inhibited Cu2+-dependent oxidation of LDL. However, neither GSSG nor methionine had any effect on Fe3+-dependent oxidation of LDL. Thus, while a free (reduced) thiol group is important for stimulation of Fe3+-dependent oxidation of LDL by CYS, HCY, and GSH, inhibition of Cu2+-dependent oxidation of LDL by these compounds seems to be thiol-independent. Our results show that thiol compounds differentially mediate Cu(2+)- and Fe3+-dependent LDL oxidation, an important early event in atherogenesis. Mediation of metal ion-dependent LDL oxidation by thiol compounds may have important implications for the etiology of atherosclerosis and may help explain the recent epidemiologic observation that plasma HCY concentration is an independent risk factor for cardiovascular disease.
Language of Publication: English
Unique Identifier: 97260381

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MeSH Heading (Major): Copper|*PD; Iron|*PD; Lipoproteins, LDL|DE/IP/*ME; Sulfhydryl Compounds|*PD
MeSH Heading: Cysteine|PD; Dose-Response Relationship, Drug; Glutathione|AA/PD; Homocysteine|PD; Human; Osmolar Concentration; Oxidation-Reduction; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Time Factors

Publication Type: JOURNAL ARTICLE
ISSN: 0006-3002
Country of Publication: NETHERLANDS

Record A86 from database: MEDLINE
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Title: Human placenta cytidine deaminase: a zinc metalloprotein.
Author: Vincenzetti S; Cambi A; Balducci E; Natalini P; Volpini R; Vita A
Address: Dipartimento di Biologia M.C.A., UniversitÄa di Camerino, Italy.
Source: Biochem Mol Biol Int, 1997 Jul, 42:3, 469-76
Abstract: Cytidine deaminase, a tetrameric enzyme purified from human placenta, was shown to contain a single atom of tightly bound zinc per subunit by Inductively Coupled Plasma Optical Emission Spectrometry analysis. The metal appears to be involved in catalysis, as suggested by the inhibition exerted by 1,10-phenanthroline and dipicolinic acid. This hypothesis is further supported by the finding that the presence of substrate protects the enzymatic activity from dipicolinic acid inhibition. Furthermore the total cysteine residues per subunit were investigated by sulphydryl groups titrating agents.
Language of Publication: English
Unique Identifier: 97390869

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MeSH Heading (Major): Cytidine Deaminase|AI/CH/*IP; Placenta|*EN; Zinc|*AN
MeSH Heading: Amino Acid Sequence; Bacterial Proteins|CH; Chelating Agents|PD; Comparative Study; Cysteine|AN; Female; Human; Molecular Sequence Data; Phenanthrolines|PD; Picolinic Acids|PD; Pregnancy; Sequence Alignment; Sequence Homology, Amino Acid; Sulfhydryl Compounds|AN

Publication Type: JOURNAL ARTICLE
ISSN: 1039-9712
Country of Publication: AUSTRALIA

Record A87 from database: MEDLINE
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Title: In vitro study of the NS2-3 protease of hepatitis C virus.
Author: Pieroni L; Santolini E; Fipaldini C; Pacini L; Migliaccio G; La Monica N
Address: I.R.B.M. Instituto di Ricerche di Biologia Molecolare P. Angeletti, Italy.
Source: J Virol, 1997 Sep, 71:9, 6373-80
Abstract: Processing at the C terminus of the NS2 protein of hepatitis C virus (HCV) is mediated by a virus-encoded protease which spans most of the NS2 protein and part of the NS3 polypeptide. In vitro cotranslational cleavage at the 2-3 junction is stimulated by the presence of microsomal membranes and ultimately results in the membrane insertion of the NS2 polypeptide. To characterize the biochemical properties of this viral protease, we have established an in vitro assay whereby the NS2-3 protease of HCV BK can be activated posttranslationally by the addition of detergents. The cleavage proficiency of several deletion and single point mutants was the same as that observed with microsomal membranes, indicating that the overall sequence requirements for proper cleavage at this site are maintained even under these artificial conditions. The processing efficiency of the NS2-3 protease varied according to the type of detergent used and its concentration. Also, the incubation temperature affected the cleavage at the 2-3 junction. The autoproteolytic activity of the NS2-3 protease could be inhibited by alkylating agents such as iodoacetamide and N-ethylmaleimide. Metal chelators such as EDTA and phenanthroline also inhibited the viral enzyme. The EDTA inhibition of NS2-3 cleavage could be reversed, at least in part, by the addition of ZnCl2 and CdCl2. Among the common protease inhibitors tested, tosyl phenylalanyl chloromethyl ketone and soybean trypsin inhibitor inactivated the NS2-3 protease. By means of gel filtration analysis, it was observed that the redox state of the reaction mixture greatly influenced the processing efficiency at the 2-3 site and that factors present in the rabbit reticulocyte lysate, wheat germ extract, and HeLa cell extract were required for efficient processing at this site. Thus, the in vitro assay should allow further characterization of the biochemical properties of the NS2-3 protease of HCV and the identification of host components that contribute to the efficient processing at the 2-3 junction.
Language of Publication: English
Unique Identifier: 97404642

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MeSH Heading (Major): Cysteine Proteinases|GE/*ME; Hepatitis C-Like Viruses|*EN/ME; Viral Nonstructural Proteins|GE/*ME
MeSH Heading: Detergents|PD; Enzyme Activation; Hela Cells; Human; Octoxynol|PD; Polyethylene Glycols|PD; Protease Inhibitors|PD; Recombinant Fusion Proteins|GE/ME

Publication Type: JOURNAL ARTICLE
ISSN: 0022-538X
Country of Publication: UNITED STATES

Record A88 from database: MEDLINE
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Title: Sequence analysis of P gene of human parainfluenza type 2 virus: P and cysteine-rich proteins are translated by two mRNAs that differ by two nontemplated G residues.
Author: Ohgimoto S; Bando H; Kawano M; Okamoto K; Kondo K; Tsurudome M; Nishio M; Ito Y
Address: Department of Microbiology, Mie University School of Medicine, Japan.
Source: Virology, 1990 Jul, 177:1, 116-23
Abstract: We cloned and sequenced the cDNAs against genomic RNA and mRNA for phosphoprotein (P) of human parainfluenza type 2 virus (PIV-2). cDNA clone from genomic RNA was 1439 nucleotides in length excluding poly(A) and was found to have two small open reading frames encoding proteins of 233 and 249 amino acids. Two different mRNA cDNA clones were obtained; that is, one mRNA contained a smaller reading frame coding 225 amino acids, V protein, and the other mRNA contained a larger reading frame coding 395 amino acids, P protein. Both mRNAs had G cluster in coding frame. The former mRNA contained seven G residues, and two extra G residues were inserted in the latter mRNA. Ten cDNA clones from the genomic RNA were identical and were composed of seven G residues, indicating that genomes analyzed here were a homogeneous population. Therefore, V protein is encoded by faithfully copied mRNA and P protein is translated from mRNA in which two additional G residues are nontemplately inserted immediately after seven genomically encoded G residues. The V and P proteins are amino coterminal proteins and have different C termini. The C terminus of V protein is cysteine-rich and bears some resemblance to metal-binding protein of the zinc finger-type motif. P protein sequence of PIV-2 showed high homologies with SV 5 (40.4%) and mumps virus (35.5%), and a moderate homology with Newcastle disease virus (20.6%). On the other hand, very little homology was found between PIV-2 and other paramyxoviruses including Sendai virus, PIV-3, and measles virus. The cysteine-rich region in V protein was found to be highly conserved in PIV-2, SV 5, and measles virus, suggesting that V protein of paramyxoviruses plays important roles in transcription and/or replication. The predicted cysteine-rich V protein was detected in virus-infected cells using antiserum directed against an oligopeptide specific for the predicted V polypeptide.
Language of Publication: English
Unique Identifier: 90281574; GENBANK/M37751

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MeSH Heading (Major): Genes, Structural, Viral|*; Guanine|*; Parainfluenza Virus 2, Human|*GE; Paramyxovirus|*GE; Phosphoproteins|*GE; Viral Proteins|*GE
MeSH Heading: Amino Acid Sequence; Animal; Base Sequence; Cell Line; Cloning, Molecular; Comparative Study; Cysteine; Gene Library; Human; Molecular Sequence Data; Paramyxoviridae|GE; Peptides|CS; RNA, Messenger|GE; RNA, Viral|GE; Templates; Translation, Genetic

Publication Type: JOURNAL ARTICLE
ISSN: 0042-6822
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (Peptides); 0 (Phosphoproteins); 0 (RNA, Messenger); 0 (RNA, Viral); 0 (Viral Proteins); 4371-52-2 (Cysteine); 73-40-5 (Guanine)

Record A89 from database: MEDLINE
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Title: Cysteine protects Na,K-ATPase and isolated human lymphocytes from silver toxicity.
Author: Hussain S; Anner RM; Anner BM
Address: Laboratory of Experimental Therapeutics, Geneva University Medical Center, Switzerland.
Source: Biochem Biophys Res Commun, 1992 Dec 30, 189:3, 1444-9
Abstract: Metal-binding proteins are important components of retroviruses such as human immunodeficiency virus (HIV). Therefore, metals could be used as antiviral agents. However, most metals are toxic for humans with the exception of silver which is toxic only to prokaryotic cells and viruses. In addition, HIV infection causes a decrease in body cysteine. We formed a complex of silver and cysteine, named silver-cysteine. Healthy human lymphocytes were incubated with silver-nitrate or silver-cysteine. Negligible cell survival was seen at 50 microM silver-nitrate. However, in presence of 1 mM cysteine, the viability remained unaffected up to 1 mM of silver. Further, silver inhibition of isolated Na,K-ATPase was easily reversed by cysteine. Thus, non-toxic silver-cysteine could be used as an anti-viral and cysteine-replenishing agent.
Language of Publication: English
Unique Identifier: 93129209

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MeSH Heading (Major): Cysteine|*PD; Lymphocytes|CY/*DE; Na(+)-K(+)-Exchanging ATPase|AI/*ME; Silver|*TO
MeSH Heading: Animal; Cell Survival|DE; Human; HIV|DE; In Vitro; Kidney Medulla|EN; Kinetics; Sheep; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0006-291X
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 3.6.1.37 (Na(+)-K(+)-Exchanging ATPase); 4371-52-2 (Cysteine); 7440-22-4 (Silver)

Record A90 from database: MEDLINE
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Title: The solution structure of the amino-terminal HHCC domain of HIV-2 integrase: a three-helix bundle stabilized by zinc.
Author: Eijkelenboom AP; van den Ent FM; Vos A; Doreleijers JF; HÁrd K; Tullius TD; Plasterk RH; Kaptein R; Boelens R
Address: Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands.
Source: Curr Biol, 1997 Oct, 7:10, 739-46
Abstract: BACKGROUND: Integrase mediates a crucial step in the life cycle of the human immunodeficiency virus (HIV). The enzyme cleaves the viral DNA ends in a sequence-dependent manner and couples the newly generated hydroxyl groups to phosphates in the target DNA. Three domains have been identified in HIV integrase: an amino-terminal domain, a central catalytic core and a carboxy-terminal DNA-binding domain. The amino-terminal region is the only domain with unknown structure thus far. This domain, which is known to bind zinc, contains a HHCC motif that is conserved in retroviral integrases. Although the exact function of this domain is unknown, it is required for cleavage and integration. RESULTS: The three-dimensional structure of the amino-terminal domain of HIV-2 integrase has been determined using two-dimensional and three-dimensional nuclear magnetic resonance data. We obtained 20 final structures, calculated using 693 nuclear Overhauser effects, which display a backbone root-mean square deviation versus the average of 0.25 A for the well defined region. The structure consists of three alpha helices and a helical turn. The zinc is coordinated with His 12 via the N epsilon 2 atom, with His16 via the N delta 1 atom and with the sulfur atoms of Cys40 and Cys43. The alpha helices form a three-helix bundle that is stabilized by this zinc-binding unit. The helical arrangement is similar to that found in the DNA-binding domains of the trp repressor, the prd paired domain and Tc3A transposase. CONCLUSION: The amino-terminal domain of HIV-2 integrase has a remarkable hybrid structure combining features of a three-helix bundle fold with a zinc-binding HHCC motif. This structure shows no similarity with any of the known zinc-finger structures. The strictly conserved residues of the HHCC motif of retroviral integrases are involved in metal coordination, whereas many other well conserved hydrophobic residues are part of the protein core.
Language of Publication: English
Unique Identifier: 98035191

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MeSH Heading (Major): HIV Integrase|*CH/DE/ME; Protein Conformation|*; Zinc|*CH
MeSH Heading: Amino Acid Sequence; Animal; Binding Sites; Chlorides|PD; Cysteine|CH; DNA|ME; Enzyme Stability; Histidine|CH; Human; Models, Molecular; Molecular Sequence Data; Nuclear Magnetic Resonance; Protein Folding; Recombinant Fusion Proteins|CH/ME; Solutions; Support, Non-U.S. Gov't; Zinc Compounds|PD

Publication Type: JOURNAL ARTICLE
ISSN: 0960-9822
Country of Publication: ENGLAND

Record A91 from database: MEDLINE
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Title: The cysteine-rich domain of human proteins, neuronal chimaerin, protein kinase C and diacylglycerol kinase binds zinc. Evidence for the involvement of a zinc-dependent structure in phorbol ester binding.
Author: Ahmed S; Kozma R; Lee J; Monfries C; Harden N; Lim L
Address: Institute of Molecular and Cell Biology, National University of Singapore.
Source: Biochem J, 1991 Nov 15, 280 ( Pt 1):, 233-41
Abstract: Diacylglycerol (DG) and its analogue phorbol 12-myristate 13-acetate (PMA) activate the ubiquitous phospholipid/Ca2(+)-d ependent protein kinase, protein kinase C (PKC), and cause it to become tightly associated with membranes. DG is produced transiently as it is rapidly metabolized by DG kinase (DGK) to phosphatidic acid. Phorbol esters such as PMA are not metabolized and induced a prolonged membrane association of PKC. Until recently, PKC was the only known phorbol ester receptor. We have shown that a novel brain-specific cDNA, neuronal chimaerin (NC), expressed in Escherichia coli, binds phorbol ester with high affinity, stereospecificity and a phospholipid requirement [Ahmed, Kozma, Monfries, Hall, Lim, Smith & Lim (1990) Biochem. J. 272, 767-773]. The proteins NC, PKC and DGK possess a cysteine-rich domain with the motif HX11/12CX2CXnCX2CX4HX2CX6/7C (where n varies between 12 and 14). The partial motif, CX2CX13CX2C, is present in a number of transcription factors including the steroid hormone receptors and the yeast protein, GAL4, in which zinc plays a structural role of co-ordinating cysteine residues and is essential for DNA binding (protein-nucleic acid interactions). The cysteine-rich domain of NC and PKC is required for phospholipid-dependent phorbol is required for phospholipid-dependent phorbol ester binding, suggesting an involvement of this domain in protein-lipid interactions. We have expressed recombinant NC, PKC and DGK glutathione S-transferase and TrpE fusion proteins in E. coli to investigate the relationship between the cysteine-rich motif, HX11/12CX2CX10-14CX2CX4HX2CX6/7C, zinc and phorbol ester binding. The cysteine-rich domain of NC, PKC and DGK bound 65Zn2+ but only NC and PKC bound [3H]phorbol 12,13-dibutyrate. When NC and PKC were subjected to treatments known to remove metal ions from GAL4 and the human glucocorticoid receptor, phorbol ester binding was inhibited. These data provide evidence for the role of a zinc-dependent structure in phorbol ester binding.
Language of Publication: English
Unique Identifier: 92074981

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MeSH Heading (Major): Cysteine|*; Nerve Tissue Proteins|GE/*ME; Phorbol 12,13-Dibutyrate|*ME; Phosphotransferases|GE/*ME; Protein Kinase C|GE/*ME; Zinc|*ME
MeSH Heading: Amino Acid Sequence; Animal; Binding Sites; Brain|EN; Cloning, Molecular; Comparative Study; DNA|GE/IP; Human; Metalloproteins|ME; Molecular Sequence Data; Mutagenesis, Site-Directed; Rats; Recombinant Fusion Proteins|ME; Restriction Mapping; Sequence Homology, Nucleic Acid; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0264-6021
Country of Publication: ENGLAND
CAS Registry/EC Number: EC 2.7 (Phosphotransferases); EC 2.7.1.- (Protein Kinase C); EC 2.7.1.107 (diacylglycerol kinase); 0 (n-chimaerin); 0 (Metalloproteins); 0 (Nerve Tissue Proteins); 0 (Recombinant Fusion Proteins); 37558-16-0 (Phorbol 12,13-Dibutyrate); 4371-52-2 (Cysteine); 7440-66-6 (Zinc); 9007-49-2 (DNA)

Record A92 from database: MEDLINE
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Title: Cysteine mapping in the ion selectivity and toxin binding region of the cardiac Na+ channel pore [published erratum appears in J Membr Biol 1997 Mar 1;156(1):98]
Author: Chen S; Hartmann HA; Kirsch GE
Address: Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA.
Source: J Membr Biol, 1997 Jan, 155:1, 11-25
Abstract: Aqueous exposure of critical residues in the selectivity region of voltage gated Na+ channels was studied by cysteine-scanning mutagenesis at three positions in each of the SS2 segments of domains III (D3) and IV (D4) of the human heart Na+ channel. Ionic currents were modified by charged cysteine-specific methanethiosulfonate (MTS) reagents, (2-aminoethyl)methanethiosulfonate (MTSEA+) and (2-sulfonatoethyl)methanethiosulfonate (MTSES-) in all six of the Cys-substituted channels, including Trp --> Cys substitutions at homologous positions in D3 and D4 that were predicted in secondary structure models to have buried side chains. Furthermore, in the absence of MTS modification, each of the Cys mutants showed a reduction in tetrodotoxin (TTX) block by a factor >10(2). Cysteine substitution without MTS modification abolished the alkali metal ion selectivity in K1418C (D3), but not in A1720C (the corresponding position in D4) suggesting that the lysine but not the alanine side chains contribute to selectivity even though both were exposed. Neither position responded to MTSES- suggesting that these residues occupy either a size- or charge-restricted region of the pore. By contrast, MTSES- markedly increased, and MTSEA+ markedly decreased conductance of D1713C (D4) suggesting that the acidic side chain of Asp1713 acts electrostatically in an unrestricted region. These results suggest that Lys1418 lies in a restricted region favorable to cations, whereas Asp1713 is at a more peripheral location in the Na+ channel pore.
Language of Publication: English
Unique Identifier: 97155940

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MeSH Heading (Major): Cysteine|*GE; Ion Channel Gating|*; Mutation|*; Myocardium|*ME; Sodium Channels|DE/*ME
MeSH Heading: Amino Acid Sequence; Carrier Proteins|DE/ME; Ethyl Methanesulfonate|AA/PD; Human; Indicators and Reagents; Molecular Sequence Data; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0022-2631
Country of Publication: UNITED STATES

Record A93 from database: MEDLINE
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Title: The amyloid precursor protein of Alzheimer's disease in the reduction of copper(II) to copper(I) [see comments]
Author: Multhaup G; Schlicksupp A; Hesse L; Beher D; Ruppert T; Masters CL; Beyreuther K
Address: ZMBH-Center for Molecular Biology Heidelberg, University of Heidelberg, Germany.
Source: Science, 1996 Mar, 271:5254, 1406-9
Abstract: The transition metal ion copper(II) has a critical role in chronic neurologic diseases. The amyloid precursor protein (APP) of Alzheimer's disease or a synthetic peptide representing its copper-binding site reduced bound copper(II) to copper(I). This copper ion-mediated redox reaction led to disulfide bond formation in APP, which indicated that free sulfhydryl groups of APP were involved. Neither superoxide nor hydrogen peroxide had an effect on the kinetics of copper(II) reduction. The reduction of copper(II) to copper(I) by APP involves an electron-transfer reaction and could enhance the production of hydroxyl radicals, which could then attack nearby sites. Thus, copper-mediated toxicity may contribute to neurodegeneration in Alzheimer's disease.
Language of Publication: English
Unique Identifier: 96173947

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MeSH Heading (Major): Alzheimer Disease|*ME; Amyloid beta-Protein Precursor|AI/CH/*ME; Copper|*ME
MeSH Heading: Binding Sites; Cysteine|CH; Cystine|ME; Electron Transport; Ferric Compounds|ME; Histidine|CH; Human; Hydrogen Peroxide|ME; Hydroxyl Radical|ME; Oligopeptides|PD; Oxidation-Reduction; Peptide Fragments|CH/ME; Recombinant Fusion Proteins|ME; Spectrum Analysis, Mass; Superoxides|ME; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0036-8075
Country of Publication: UNITED STATES

Record A94 from database: MEDLINE
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Title: Identification of an ATPase activity associated with a 71-kilodalton polypeptide encoded in gene 1 of the human coronavirus 229E.
Author: Heusipp G; Harms U; Siddell SG; Ziebuhr J
Address: Institute of Virology, University of WÂurzburg, Germany.
Source: J Virol, 1997 Jul, 71:7, 5631-4
Abstract: Human coronavirus 229E gene expression involves proteolytic processing of the gene 1-encoded polyproteins pp1a and pp1ab. In this study, we have detected a 71-kDa polypeptide in virus-infected cells that is released from pp1ab by the virus-encoded 3C-like proteinase and that has been predicted to contain both metal-binding and helicase domains. The polypeptide encompasses amino acids Ala-4996 to Gln-5592 of pp1ab and exhibits nucleic acid-stimulated ATPase activity when expressed as a fusion protein with the Escherichia coli maltose-binding protein. These data provide the first identification of a coronavirus open reading frame 1b-encoded enzymatic activity.
Language of Publication: English
Unique Identifier: 97332405

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MeSH Heading (Major): Adenosinetriphosphatase|GE/*ME; Coronavirus, Human|*EN/GE; Peptides|GE/*ME; Viral Proteins|GE/*ME
MeSH Heading: Adenosine Triphosphate|ME; Binding Sites; Cell Line; Cysteine Proteinases|ME; Human; Recombinant Fusion Proteins|GE/ME; Support, Non-U.S. Gov't

Publication Type: JOURNAL ARTICLE
ISSN: 0022-538X
Country of Publication: UNITED STATES

Record A95 from database: MEDLINE
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Title: The autoimmunity-inducing xenobiotic mercury interacts with the autoantigen fibrillarin and modifies its molecular and antigenic properties.
Author: Pollard KM; Lee DK; Casiano CA; Bluthner M; Johnston MM; Tan EM
Address: Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA.
Source: J Immunol, 1997 Apr, 158:7, 3521-8
Abstract: The heavy metal mercury elicits a genetically restricted, anti-nucleolar autoantibody response that targets fibrillarin, a 34-kDa protein component of many small nucleolar ribonucleoprotein particles. The mechanisms by which a toxin such as mercury elicits an autoantibody response that predominantly targets a single intracellular protein autoantigen remain uncertain, but may be prefaced by mercury gaining access to the intracellular environment. Mercury-induced cell death was associated with loss of fibrillarin antigenicity and modification of the molecular properties of fibrillarin as revealed by aberrant migration under nonreducing conditions in SDS-PAGE. Addition of mercury to isolated nuclei also resulted in aberrant migration of fibrillarin, but not other nuclear autoantigens. The sensitivity of the HgCl2-induced modification of fibrillarin to 2-ME, iodoacetamide, and hydrogen peroxide suggested interaction of mercury with the two cysteines in the fibrillarin sequence. This was confirmed by mutation of the cysteines to alanines, which abolished the aberrant migration of fibrillarin in the presence of HgCl2. The modification of the molecular structure of fibrillarin by mercury reduced immunoprecipitation by anti-fibrillarin autoantibodies, pointing to unmodified fibrillarin as the B cell Ag and implicating mercury-modified fibrillarin as the source of T cell antigenicity. These observations demonstrate for the first time that an environmental toxin can alter the physicochemical properties of an autoantigen and may help to explain the antigenic specificity of mercury-induced murine autoimmunity.
Language of Publication: English
Unique Identifier: 97240801

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MeSH Heading (Major): Autoantigens|*DE/*IM; Chromosomal Proteins, Non-Histone|DE/*IM/*PD; Mercuric Chloride|*IM/*PD; Xenobiotics|*IM/*PD
MeSH Heading: Antibodies, Monoclonal|CH; Autoantibodies|ME; Binding Sites, Antibody; Cell Death|DE/IM; Cell Nucleus|DE/IM; Cysteine|PH; Disulfides|CH; Electrophoresis, Polyacrylamide Gel; Epitopes|CH; Human; Subcellular Fractions|DE/IM; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0022-1767
Country of Publication: UNITED STATES

Record A96 from database: MEDLINE
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Title: Short related sequences in the cytoplasmic domains of CD4 and CD8 mediate binding to the amino-terminal domain of the p56lck tyrosine protein kinase.
Author: Shaw AS; Chalupny J; Whitney JA; Hammond C; Amrein KE; Kavathas P; Sefton BM; Rose JK
Address: Department of Pathology, Yale School of Medicine, Yale University, New Haven, Connecticut 06510.
Source: Mol Cell Biol, 1990 May, 10:5, 1853-62
Abstract: We report that the cytoplasmic domains of the T-lymphocyte glycoproteins CD4 and CD8 alpha contain short related amino acid sequences that are involved in binding the amino-terminal domain of the intracellular tyrosine protein kinase, p56lck. Transfer of as few as six amino acid residues from the cytoplasmic domain of the CD8 alpha protein to the cytoplasmic domain of an unrelated protein conferred p56lck binding to the hybrid protein in HeLa cells. The common sequence motif shared by CD4 and CD8 alpha contains two cysteines, and mutation of either cysteine in the CD4 sequence eliminated binding of p56lck.p56lck also contains two cysteine residues within its CD4-CD8 alpha-binding domain, and both are critical to the interaction with CD4 or CD8 alpha. Because the interaction does not involve disulfide bond formation, a metal ion could stabilize the complex.
Language of Publication: English
Unique Identifier: 90220568

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MeSH Heading (Major): Antigens, CD4|*ME; Antigens, Differentiation, T-Lymphocyte|*ME; Protein-Tyrosine Kinase|*ME
MeSH Heading: Amino Acid Sequence; Base Sequence; Cysteine|PH; Cytoplasm|ME; DNA Mutational Analysis; Human; In Vitro; Molecular Sequence Data; Protein Binding; Signal Transduction; Structure-Activity Relationship; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0270-7306
Country of Publication: UNITED STATES
CAS Registry/EC Number: EC 2.7.1.- (lymphocyte specific protein tyrosine kinase p56(lck)); EC 2.7.1.112 (Protein-Tyrosine Kinase); 0 (Antigens, CD4); 0 (Antigens, CD8); 0 (Antigens, Differentiation, T-Lymphocyte); 4371-52-2 (Cysteine)

Record A97 from database: MEDLINE
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Title: Metal ion and salt effects on the phospholipase A2, lysophospholipase, and transacylase activities of human cytosolic phospholipase A2.
Author: Reynolds LJ; Hughes LL; Louis AI; Kramer RM; Dennis EA
Address: Department of Chemistry, University of California, San Diego, La Jolla 92093-0601.
Source: Biochim Biophys Acta, 1993 Apr 23, 1167:3, 272-80
Abstract: Human cytosolic phospholipase A2 (cPLA2) is an arachidonic acid specific enzyme which may play a role in arachidonic acid release, eicosanoid production, and signal transduction. The PLA2 activity of this enzyme is stimulated by microM levels of Ca2+. Using a pure recombinant enzyme, we have confirmed that cPLA2 is not absolutely dependent on Ca2+, since Sr2+, Ba2+ and Mn2+ also gave full enzyme activity. Heavy metals, in contrast, inhibited enzyme catalysis suggesting the involvement of an essential cysteine residue. In the absence of Ca2+, high salt concentrations overcame the requirement for divalent metals, indicating that Ca2+ is not required for PLA2 catalytic activity. cPLA2 also displays a lysophospholipase (lyso PLA) activity with lysophosphatidylcholine micelles as a substrate. Unlike the PLA2 activity, the lyso PLA activity toward these micelles is not stimulated by Ca2+. However, upon the addition of glycerol or Triton X-100 to the assay, Ca2+ activation is observed, indicating that substrate presentation can affect the apparent Ca2+ dependence. Glycerol was found to be a potent stimulator of lyso PLA activity and specific activities up to 50 mumol min-1 mg-1 were observed. In addition to the PLA2 and lyso PLA activities, we report that cPLA2 displays a relatively low, CoA-independent transacylase activity which produces phosphatidylcholine from lysophosphatidylcholine substrate. The observation of this novel transacylase activity is consistent with the formation of an acyl-enzyme intermediate.
Language of Publication: English
Unique Identifier: 93244275

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MeSH Heading (Major): Acyltransferases|*ME; Lysophospholipase|*ME; Metals|*PD; Phospholipases A|*ME; Salts|*PD
MeSH Heading: Calcium|PD; Cations, Divalent; Cytosol|DE/ME; Enzyme Activation|DE; Human; Lysophosphatidylcholines|ME; Recombinant Proteins|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type: JOURNAL ARTICLE
ISSN: 0006-3002
Country of Publication: NETHERLANDS
CAS Registry/EC Number: EC 2.3. (Acyltransferases); EC 3.1.1.- (Phospholipases A); EC 3.1.1.5 (Lysophospholipase); 0 (Cations, Divalent); 0 (Lysophosphatidylcholines); 0 (Metals); 0 (Recombinant Proteins); 0 (Salts); 7440-70-2 (Calcium)

Record A98 from database: MEDLINE
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Title: The mechanism of Hg2+ toxicity in cultured human oral fibroblasts: the involvement of cellular thiols.
Author: Liu Y; Cotgreave I; Atzori L; Grafström RC
Address: Department of Toxicology, Karolinska Institutet, Stockholm, Sweden.
Source: Chem Biol Interact, 1992 Nov 30, 85:1, 69-78
Abstract: To study amalgam-related toxicity in a primary target cell type, human oral fibroblasts were grown in a low-serum medium containing 1.25% fetal bovine serum and exposed to Hg2+, a corrosion product of amalgam. A 1-h exposure to various concentrations of Hg2+ resulted in a dose-dependent loss of colony forming efficiency. Removal of the low-molecular-weight thiol cysteine from the medium increased the toxicity of Hg2+ almost 50-fold in comparison with complete medium or medium without fetal bovine serum. Accordingly, fetal bovine serum was not found to contain detectable levels of low-molecular-weight thiols. The levels of cellular free protein thiols were shown to be depleted Hg2+ at significantly lower concentrations of the metal ion than those required to decrease the levels of the major cellular low-molecular weight thiol glutathione. These decreases were dependent on the exposure conditions, i.e. the presence of serum and thiols, in a manner similar to the effect on colony forming efficiency. Other functions commonly related to cell viability, including the accumulation of the vital dye neutral red, the cytosolic retention of deoxyglucose and the mitochondrial reduction of tetrazolium were also inhibited by Hg2+, albeit at higher concentrations. Finally, the depletion of cellular glutathione, by pre-exposure of the cells to the glutathione synthesis inhibitor buthionine sulfoximine, somewhat increased the toxicity of Hg2+ and potentiated the depletion of protein thiols. Taken together, the toxicity of Hg2+ in human oral fibroblasts was demonstrated in several assays of which colony forming efficiency was the most sensitive, cell killing by this agent was related to its high affinity for protein thiols, whereas glutathione showed a significant, but limited, ability to protect the cells from Hg2+ toxicity.
Language of Publication: English
Unique Identifier: 93092228

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MeSH Heading (Major): Dental Amalgam|*TO; Fibroblasts|*CY/DE/ME; Mercury|PD/*TO; Mouth|*CY; Sulfhydryl Compounds|*ME
MeSH Heading: Cell Division|DE; Cell Survival|DE; Cells, Cultured; Cysteine|ME; Deoxyglucose|ME; Dyes; Glutathione|ME; Human; Methionine Sulfoximine|AA/PD; Neutral Red|ME; Support, Non-U.S. Gov't; Tetrazolium Salts|ME; Thiazoles|ME

Publication Type: JOURNAL ARTICLE
ISSN: 0009-2797
Country of Publication: NETHERLANDS
CAS Registry/EC Number: 0 (Dyes); 0 (Sulfhydryl Compounds); 0 (Tetrazolium Salts); 0 (Thiazoles); 154-17-6 (Deoxyglucose); 1982-67-8 (Methionine Sulfoximine); 298-93-1 (thiazolyl blue); 4371-52-2 (Cysteine); 5072-26-4 (Buthionine Sulfoximine); 553-24-2 (Neutral Red); 70-18-8 (Glutathione); 7439-97-6 (Mercury); 8049-85-2 (Dental Amalgam)

Record A99 from database: MEDLINE
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Title: Maleimidocysteineamido-DOTA derivatives: new reagents for radiometal chelate conjugation to antibody sulfhydryl groups undergo pH-dependent cleavage reactions.
Author: Lewis MR; Shively JE
Address: City of Hope Graduate Program in Biological Sciences, Duarte, California 91010, USA.
Source: Bioconjug Chem, 1998 Jan, 9:1, 72-86
Abstract: We have synthesized two bifunctional derivatives of the macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"-tetraacetic acid (DOTA) equipped with maleimide groups for conjugation to reduced disulfide bonds of monoclonal antibodies. Using water-soluble carbodiimide chemistry, DOTA was coupled to L-cysteine to incorporate both a "pendant-type" carboxyl group for metal coordination and an orthogonal thiol group for protein attachment. The homobifunctional reagent 1,6-bis(maleimido)hexane was then used to introduce the maleimide functionality via a sulfide linkage to the macrocycle, and alternatively, the sulfide group was converted to a sulfone side chain. Both maleimide derivatives were conjugated to the anticarcinoembryonic antigen chimeric monoclonal antibody cT84.66 after light reduction of the mAb with dithiothreitol. In this manner, antibody conjugates were prepared which afforded near-quantitative labeling with the radiometals 111In(III) and 90Y(III) as well as quantitative immunoreactivity. Radioimmunoconjugates prepared with the sulfide and sulfone compounds exhibited relatively rapid linker-dependent radiometal loss when incubated in human serum and aqueous solutions at physiological temperature and pH. The unconjugated maleimidocysteineamido-DOTA derivatives and their Y(III) complexes were incubated in aqueous solution at 37 degrees C, and the resulting decomposition products were analyzed by HPLC and mass spectrometry. These studies revealed that the two bifunctional chelating agents underwent linker-specific cleavage reactions which were considerably faster at pH 7.4 than at pH 5.4. The chemically labile linker systems are expected to release chelated radiometal from mAb conjugates in a pH-dependent manner. This property may impart favorable tumor uptake and normal tissue clearance on radioimmunoconjugates prepared with these reagents, on the basis of the observation that many solid tumors are significantly more acidic than normal tissues.
Language of Publication: English
Unique Identifier: 98121881

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MeSH Heading (Major): Antibodies, Monoclonal|*CH; Chelating Agents|*CS; Cysteine|*CH; Disulfides|*CH; Heterocyclic Compounds|*CH; Maleimides|*CH
MeSH Heading: Blood; Carcinoembryonic Antigen|IM; Chromatography, High Pressure Liquid; Dithiothreitol|CH; Drug Stability; Human; Hydrogen-Ion Concentration; Indicators and Reagents; Indium Radioisotopes; Molecular Structure; Oxidation-Reduction; Solutions; Spectrum Analysis, Mass; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.; Yttrium Radioisotopes

Publication Type: JOURNAL ARTICLE
ISSN: 1043-1802
Country of Publication: UNITED STATES

Record A100 from database: MEDLINE
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Title: Role of oxygen and metal ions in the instability of streptolysin O.
Author: Shoeb HA
Address: Department of Pharmaceutics/Microbiology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
Source: Biotechnol Appl Biochem, 1991 Dec, 14:3, 383-7
Abstract: Thiol-containing preparations of streptolysin O (SLO) and pure cysteine generate superoxide radicals in alkaline buffer on autoxidation of the thiol groups. Autoxidation is stimulated by cupric ions. Reconstituted SLO preparations accumulate hydrogen peroxide with a concomitant loss of activity on storage at room temperature. Short-term protection of hemolytic activity was achieved by inclusion of catalase in the preparation; no apparent protection was observed by superoxide dismutase, whereas 1,10-O-phenanthroline offered long-term protection of the hemolysin.
Language of Publication: English
Unique Identifier: 92134608

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MeSH Heading (Major): Metals|*ME; Oxygen|*ME; Streptolysins|CH/*ME
MeSH Heading: Hemolysis; Human; Kinetics

Publication Type: JOURNAL ARTICLE
ISSN: 0885-4513
Country of Publication: UNITED STATES
CAS Registry/EC Number: 0 (streptolysin O); 0 (Metals); 0 (Streptolysins); 7782-44-7 (Oxygen)

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