Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The glutathione S-transferases (GSTs) of hepatic cytosol of rats, mice, guinea pigs, rabbits and hamsters were simultaneously investigated with respect to substrate specificity, subunit composition and elution profile of GSTs. The activity towards 1-chloro-2,4-dinitrobenzene was the highest in hamsters, followed by rabbits, guinea pigs, mice and rats. On the analysis of SDS-PAGE, Ya subunit band of GST was detected in only rats, not others. There was also seen a marked species difference in elution profile of GST activity on S-sepharose column. The elution patterns from rats, mice and rabbits were quite different from hamsters and guinea pigs.
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PMID:Comparison of glutathione S-transferases in mouse, guinea pig, rabbit and hamster liver cytosol to those in rat liver. 380 Oct 38

The purification of a hybrid glutathione S-transferase (B1 B2) from human liver is described. This enzyme has an isoelectric point of 8.75 and the B1 and B2 subunits are distinguishable immunologically and are ionically distinct. Hybridization experiments demonstrated that B1 B1 and B2 B2 could be resolved by CM-cellulose chromatography and have pI values of 8.9 and 8.4 respectively. Transferase B1 B2, and the two homodimers from which it is formed, are electrophoretically and immunochemically distinct from the neutral enzyme (transferase mu) and two acidic enzymes (transferases rho and lambda). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that B1 and B2 both have an Mr of 26 000, whereas, in contrast, transferase mu comprises subunits of Mr 27 000 and transferases rho and lambda both comprise subunits of Mr 24 500. Antisera raised against B1 or B2 monomers did not cross-react with the neutral or acidic glutathione S-transferases. The identity of transferase B1 B2 with glutathione S-transferase delta prepared by the method of Kamisaka, Habig, Ketley, Arias & Jakoby [(1975) Eur. J. Biochem. 60, 153-161] has been demonstrated, as well as its relationship to other previously described transferases.
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PMID:Identification of a basic hybrid glutathione S-transferase from human liver. Glutathione S-transferase delta is composed of two distinct subunits (B1 and B2). 400 74

We have shown earlier that there are large, hereditary interindividual differences in the cytosolic glutathione transferase activity towards trans-stilbene oxide in human mononuclear leukocytes. In the present study we ask whether these differences reflect the presence or absence of a particular isozyme(s) of glutathione transferase. First, in order to measure the high glutathione transferase activity optimally it was necessary to modify our previous assay by increasing the concentration of reduced glutathione from 3 to 5 mM and of the substrate from 50 to 250 microM. It was then found that the low activity demonstrates an apparent Km for trans-stilbene oxide of 28.3 microM, whereas the corresponding value for the high activity was 127 microM. Secondly, it was found that while glutathione transferase activity towards trans-stilbene oxide in different individuals segregated into three groups, low, high and very high, glutathione transferase activity towards 1-chloro-2,4-dinitrobenzene in these same mononuclear leukocyte fractions formed only a single group with no tendency towards such segregation. Thirdly, the SDS-poly-acrylamide gel electrophoretic pattern obtained with the supernatant fraction from mononuclear cells demonstrating high glutathione transferase activity towards trans-stilbene oxide contained a band of 25 000 molecular weight which was either absent or present at a much lower level in cells demonstrating low activity. We conclude that high activity towards trans-stilbene oxide in circulating, resting human mononuclear cells is catalyzed by a particular isozyme(s) of glutathione transferase. cis-Stilbene oxide, styrene oxide and, possibly, benzo[a]pyrene 4,5-oxide are also substrates for this isozyme(s).
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PMID:Hereditary interindividual differences in the glutathione transferase activity towards trans-stilbene oxide in resting human mononuclear leukocytes are due to a particular isozyme(s). 401 89

The activities of hepatic cytosolic glutathione S-transferases (GSTs) towards 1,2-dichloro-4-nitrobenzene in male rats were higher than those in females, however, the enzyme activities towards 1-chloro-2,4-dinitrobenzene were not significantly different between the two sexes. SDS-PAGE analysis of GSTs purified from male and female rat hepatic cytosols by affinity column chromatography showed that there was a significant difference in the subunit composition between the two sexes. With regard to the several isozymes of GSTs in male and female rats, isozymes with basic and neutral/acidic isoelectric points were separated into seven molecular species by chromatofocusing. These sex differences in the quantitative proportions of GST isozymes were also confirmed by immunotitration using anti-GST-BL and -AC antibodies. On the other hand, glutathione peroxidase (GSH-Px) activities in rat hepatic cytosol towards hydrogen peroxide and cumene hydroperoxide were markedly higher in females than in males. Of the two types of GSH-Px, selenoenzyme (Se-GSH-Px) and the Se-independent enzyme (non-Se-GSH-Px), the former was found to be mainly responsible for the sex difference in the enzyme activities. Moreover, the GSH-Px activity of GSTs, non-Se-GSH-Px, was also higher in females than that in males. Since GST isozymes of the BL type are known to possess GSH-Px activity towards cumene hydroperoxide, the increased activities of non-Se-GSH-Px in the female hepatic cytosol seemed to be mainly due to the increased transferase activities of the isozymes, GST-L2 and -BL.
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PMID:Sex difference in subunit composition of hepatic glutathione S-transferase in rats. 404 45

The hepatic glutathione S-transferase (GST) activity in the cytosol of the freshwater fish carp (Cyprinus carpio) was enriched by glutathione affinity chromatography. The anionic (GST A1-A3) and cationic (GST C1-C3) isoenzymes were then separated in two chromatofocusing steps. SDS electrophoresis showed GST C1 to be a heterodimer with subunits of Mr 25,000 and 28,000, and all other isoenzymes to be homodimers with subunits of Mr 25,400. They were partially characterized by different biochemical parameters. The water pollutants 2,4-dichlorophenoxyacetic acid and 1,4-benzoquinone inhibited all carp GST isoenzymes, following the same kinetic inhibition patterns as for rat liver GST. It is concluded that hepatic carp GST can play an important role in the detoxication of aquatic pollutants.
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PMID:Purification and partial characterization of the glutathione S-transferases in carp liver, and their interaction with 2,4-dichlorophenoxyacetic acid and 1,4-benzoquinone. 409 50

We describe the construction and characterization of a cDNA plasmid for one of the rat liver glutathione S-transferase subunits. Poly(A)-RNA isolated from rat livers was enriched for glutathione S-transferase mRNA activity and used as templates to synthesize double stranded cDNA. The double stranded cDNAs were annealed to pBR322 through terminal deoxynucleotidyl transferase generated GC-tails followed by transformation into E. coli. Several candidate clones were selected by colony hybridization using polynucleotide kinase labeled liver and testis poly(A)-RNA probes. These candidate clones were further characterized by hybrid-selected translation of mRNA followed by immunoprecipitation and SDS gel electrophoresis. The positive clone, pGTR112 was mapped with restriction endonuclease analysis and sequenced by the chemical method of Maxam and Gilbert. The largest upen reading frame contains 142 amino acids very rich in Arg and Lys residues. The C-terminal residue phenylalanine of this open reading frame is consistent with what was reported for one of the ligandin subunits by Bhargava et al., (J. Biol. Chem. 253, 4116-4119, 1978). Among the 352 nucleotides covered by both pGTR112 and pGST94 described by Kalinyak and Taylor (J. Biol. Chem. 257, 523-530, 1982), there are only 9 nucleotide differences resulting in four changes of amino acid sequences.
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PMID:Cloning and sequence analysis of a cDNA plasmid for one of the rat liver glutathione S-transferase subunits. 629 39

Elevations in intracellular calcium increase the adsorption of a cytoplasmic protein to human red blood cell membrane. This protein migrates on SDS polyacrylamide gels at 23,000 daltons and has been called band 8. The association of this protein with the membrane is increased in sickle cell anemia. This protein is extracted from the membrane with EGTA, a calcium chelator. Enzymatic and immunological studies identify band 8 as a glutathione S-transferase.
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PMID:Calcium-dependent association of glutathione S-transferase with the human erythrocyte membrane. 641 Oct 89

A new glutathione S-transferase has been purified to homogeneity from 105,000 X g supernatant of Sprague-Dawley rat liver homogenates. The purified enzyme exhibited specific activities of approximately 1.8, and 0.12 mumoles X min-1 X mg-1 toward 1-chloro 2,4-dinitrobenzene and cumene hydroperoxide respectively. The SDS gel electrophoresis data on subunit composition revealed that the new transferase is composed of two subunits with an identical Mr of 24,400 (Y alpha Family). Our in vitro translation experiments with rat liver poly(A) RNAs and substrate specificity data suggest that this subunit is different from the previously reported Ya , Yb and Yc subunits of rat liver glutathione S-transferases. Comparatively, the new isozyme showed significant activity toward 1,2 epoxy-3-(P-nitrophenoxy)-propane, ethacrynic acid and P-nitrophenyl acetate, 0.4, 0.34 and 0.18 mumoles. min-1 X mg-1 respectively.
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PMID:Identification of a new glutathione S-transferase from rat liver cytosol. 674 13

An anionic glutathione S-transferase representing approximately 20% of the total glutathione S-transferase protein and 10% of the total transferase activity toward 1-chloro 2,4-dinitrobenzene has been purified to homogeneity from the 105,000 x g supernatant of rat liver homogenate. The SDS gel electrophoretic data on subunit composition revealed that the anionic isozyme is composed of two subunits with an identical Mr of 26,000. The Km values for 1-chloro 2,4-dinitrobenzene and reduced glutathione were determined to be 0.94 mM and 0.23 mM respectively. A significant amount of glutathione peroxidase activity toward cumene hydroperoxide is associated with the new isozyme.
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PMID:Isolation and characterization of an anionic glutathione S-transferase from rat liver cytosol. 683 89

The glutathione S-transferases (EC 2.5.1.18) have been purified to electrophoretic homogeneity from 105,000g supernatant of sheep liver homogenate by employing a combination of gel filtration on Sephadex G-150 and affinity chromatography on S-hexylglutathione-linked Sepharose-6B columns. Approximately 70% of the original glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene and glutathione peroxidase activity toward cumene hydroperoxide could be recovered by this purification method. Of particular importance in developing this procedure was the fact that the enzyme preparation obtained after affinity column chromatography represented all the isozymes of sheep liver glutathione S-transferases. Further purification by CM-cellulose and DEAE-cellulose column chromatography resolved the glutathione S-transferases into seven distinct cationic isozymes designated C-1, C-2, C-3, C-4, C-5, C-6, and C-7 and five overlapping anionic transferases designated A-1, A-2, A-3, A-4, and A-5, respectively, in the order of their elution from the ion-exchange columns. The sodium dodecyl sulfate SDS-gel electrophoretic data on subunit composition revealed that cationic enzymes are composed of two subunits with an identical Mr of 24,000 whereas a predominant subunit with Mr of 26,000 was observed in all anionic isozyme peaks except A-1. Cationic isozymes accounted for approximately 98% of the total peroxidase activity associated with the glutathione S-transferase whereas only A-1 of the anionic isozymes displayed some peroxidase activity. Isozyme C-4 was found to be the most abundant glutathione S-transferase in the sheep liver. Characterization of the individual transferases by their specificity toward a number of selected substrates, subunit composition, and isoelectric points showed some similarities to those patterns for human liver glutathione S-transferases.
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PMID:Purification and characterization of the individual glutathione S-transferases from sheep liver. 687 Feb 66


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