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)

Human muscle glutathione S-transferase isozyme, GST zeta (pI 5.2) has been purified by three different methods using immunoaffinity chromatography, DEAE cellulose chromatography, and isoelectric focusing. GST zeta prepared by any of the three methods does not recognize antibodies raised against the alpha, mu, or pi class glutathione S-transferases of human tissues. GST zeta has a blocked N-terminus and its peptide fingerprints also indicate it to be distinct from the alpha, mu, or pi class isozymes. As compared to GSTs of alpha, mu, and pi classes, GST zeta displays higher activities toward t-stilbene oxide and Leukotriene A4 methyl ester. GST zeta also expresses GSH-peroxidase activity toward hydrogen peroxide. The Kms of GST zeta for CDNB and GSH were comparable to those reported for other human GSTs but its Vmax for CDNB, 7620 mol/mol/min, was found to be considerably higher than that reported for other human GSTs. The kinetics of inhibition of GST zeta by hematin, bile acids, and other inhibitors also indicate that it was distinct from the three classes of GST isozymes. These studies suggest that GST zeta corresponds to a locus distinct from GST1, GST2, and GST3 and probably corresponds to the GST4 locus as suggested previously by Laisney et al. (1984, Human Genet. 68, 221-227). The results of peptide fingerprints and kinetic analysis indicate that as compared to the pi and alpha class isozymes, GST zeta has more structural and functional similarities with the mu class isozymes. Besides GST zeta several other GST isozymes belonging to pi and mu class have also been characterized in muscle. The pi class GST isozymes of muscle have considerable charge heterogeneity among them despite identical N-terminal sequences.
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PMID:Purification and characterization of human muscle glutathione S-transferases: evidence that glutathione S-transferase zeta corresponds to a locus distinct from GST1, GST2, and GST3. 184 34

We have investigated the longitudinal distribution of glutathione S-transferase (GST) isozymes in the trisected small intestine mucosa of rats. Only GST subunits 1 and 7 were detected by Western blot analysis of the intestinal cytosol using antiserum for GST1-1, 1-2, 3-4 and 7-7. Cytosolic GST1-1, 3-4 and 7-7 were assayed by the quantitative ELISA. There was a marked decline of the concentration of GST1-1 from proximal (35.17 nmol/g tissue) to distal intestine (1.67 nmol/g tissue). GST3-4 was hardly detected in the intestinal mucosa. Among the GSTs, GST7-7 existed in the highest concentration in any segment of intestine, i.e. 58.76 nmol/g tissue (61% of GSTs) in the proximal intestine and 32.38 nmol/g tissue (93% of GSTs) in the distal intestine.
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PMID:[Distribution of glutathione S-transferase isozymes in rat small intestinal mucosa]. 188 Sep 50

An acidic glutathione S-transferase (GST) isoenzyme termed GST6 has been isolated from human brain, characterized and compared with other isoenzymes. The N-terminal amino acid sequence of GST6 was found to be identical with that of GST4 previously purified from human muscle. GST6 cross-reacted with antibody raised against GST4, but not with antisera raised against GST1, GST2 or GST3. The subunit Mr and pI of GST6 were found to be different from those of GST4. The present results indicate that GST6 is another member of the Mu evolutionary class which in man also includes GST1, GST4 and GST5. A minor component that co-purified with GST6 was shown to have an N-terminal sequence similar to, but not identical with, that of GST3. This isoenzyme may be an additional member of the Pi evolutionary class.
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PMID:Purification and characterization of acidic glutathione S-transferase 6 from human brain. 200 8

The products of three human glutathione S-transferase (RX:glutathione R-transferase, EC 2.5.1.18) (GST) loci (GST 1, GST 2 and GST 3) were purified and their immunohistochemical localization in liver was studied with special attention to the polymorphism of GST1 (neutral isozyme). The GST1 was homogeneously stained in cytoplasm of hepatocytes throughout the lobule of liver showing GST1 1, GST1 2 and GST1 2-1 phenotypes. However, none of the hepatic tissue showing GST1 0 phenotype was stained. Immunohistochemical staining of GST2 (basic isozyme) was distributed in the cytoplasm of hepatocytes homogeneously throughout the hepatic lobule in all cases and the strong staining intensity was also demonstrated in nucleus. GST3 (acidic isozyme) was strongly stained in biliary epithelium, while staining of hepatocytes was not apparent. These results indicate that the human liver GST isozymes exhibit significant difference in their inter-individual, specific cellular and organellar distribution.
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PMID:Immunohistochemical localization of human liver glutathione S-transferase (GST) isozymes with special reference to polymorphic GST1. 246 63

The products of three human glutathione S-transferase (GST) loci (GST1, GST2 and GST3) were purified and their immunochemical properties as well as immunohistological localization in liver were studied. Three group of isozymes were different in molecular weight, substrate specificities and antigenicity. Two homodimers (type 1 and type 2) of GST1 which shows genetic polymorphism, were similar in immunochemical properties other than isoelectric point. Inactivity of GST1 0 was due to impaired protein synthesis. Immunohistologically, GST1 isozyme was homogeneously stained in cytoplasm of hepatocytes throught the lobule of liver showing GST1 1, GST1 2 and GST1 2-1 phenotypes. On the other hand, GST2 isozyme was stained in the cytoplasm as well as the nucleus of hepatocytes throughout the hepatic lobule in all cases. GST3 isozyme was strongly stained in biliary epithelium. These results indicate that the human liver GSTs are composed of three immunochemically distinct isozymes, which exhibit significant difference in inter-individual, specific cellular and organellar distribution.
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PMID:[Immunochemical properties and immunohistological localization of human liver glutathione S-transferase isozymes]. 262 19

Several forms of glutathione S-transferase (GST) are present in human kidney, and the overall isoenzyme pattern of kidney differs significantly from those of other human tissues. All the three major classes of GST isoenzymes (alpha, mu and pi) are present in significant amounts in kidney, indicating that GST1, GST2 and GST3 gene loci are expressed in this tissue. More than one form of GST is present in each of these classes of enzymes, and individual variations are observed for these classes. The structural, immunological and functional properties of GST isoenzymes of three classes differ significantly from each other, whereas the isoenzymes belonging to the same class have similar properties. All the cationic GST isoenzymes of human kidney except for GST 9.1 are heterodimers of 26,500-Mr and 24,500-Mr subunits. GST 9.1 is a dimer of 24,500-Mr subunits. All the cationic isoenzymes of kidney GST cross-react with antibodies raised against a mixture of GST alpha, beta, gamma, delta and epsilon isoenzymes of liver. GST 6.6 and GST 5.5 of kidney are dimers of 26,500-Mr subunits and are immunologically similar to GST psi of liver. Unlike other human tissues, kidney has at least two isoenzymes (pI 4.7 and 4.9) associated with the GST3 locus. Both these isoenzymes are dimers of 22,500-Mr subunits and are immunologically similar to GST pi of placenta. Some of the isoenzymes of kidney do not correspond to known GST isoenzymes from other human tissues and may be specific to this tissue.
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PMID:Purification and characterization of glutathione S-transferases of human kidney. 311 68

Immunocytochemical studies demonstrate that significant amounts of glutathione S-transferase (GST) are associated with alveoli and bronchioles of human lung. The immunofluorescence in human lung sections was observed with the antibodies which were raised against GST psi and GST alpha-epsilon of human liver and GST pi of human placenta indicating that the isoenzymes corresponding to three gene loci, GST1, GST2, and GST3 are present in human lung. Presence of GST isoenzymes in significant amounts in bronchioles and alveoli of human lung indicate that these isoenzymes may play an important role in the detoxification of xenobiotics as well as in combating oxidative stress through glutathione peroxidase II activity.
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PMID:Immunocytochemical evidence for the expression of GST1, GST2, and GST3 gene loci for glutathione S-transferase in human lung. 312 4

Results of studies designed to investigate the origin of the diversity of glutathione S-transferase (GST) isozymes in human tissues indicated that human muscle has at least three forms of GST with pI values of 5.0, 5.1, and 5.2 that are distinct from GST isozymes characterized so far. The major muscle isozyme which was expressed in all the six samples analyzed in this study was a unique GST of pI 5.2 that was designated as GST zeta. It had a blocked N-terminal and did not correspond to any of the known three classes (alpha, mu, or pi) of human GST as evidenced by its immunological properties and substrate specificities. The N-terminal regions of human muscle GST 5.1 and 5.0 had identical amino acid sequences except at residue 5, but demonstrated significant differences in amino acid composition and substrate specificities. These two isozymes showed homology with the mu class of human GST in their N-terminal region and were also immunologically related to the mu class of human GST although their subunit molecular weight values (Mr 23,000) were lower than that reported for GST psi. The substrate specificities of these isozymes were also significantly different from those of other human GST isozymes characterized so far. Significantly, muscle tissue did not express the alpha class of GST isozymes; however, two other isozymes were identified, GST 4.8 and GST 4.5, which had identical N-terminal amino acid sequences that were similar to that reported for the pi class of human GST. GST 4.8 was present in all six samples analyzed in this study whereas GST 4.5 was present in only two of these samples, indicating a possibility of polymorphism at the GST3 locus. This study indicated the occurrence of at least three distinct isozymes in muscle tissue, providing further evidence for tissue specific expression of GST isozymes in humans.
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PMID:Purification and characterization of unique glutathione S-transferases from human muscle. 339 18

A total of 168 autopsy liver extracts from Japanese individuals were examined for the glutathione S-transferase (GST) isozymes by means of starch gel electrophoresis. The gene frequencies of GST1*1, GST1*2, and GST1*0 in Japanese were 0.252, 0.057, and 0.691, respectively. GST1*3 was detected as a rare variant allele. The incidence of GST1 0 in 41 liver biopsy samples from patients suffering from various liver diseases was investigated using polyacrylamide gel isoelectric focusing. The GST1 0 phenotype was found more frequently in livers with hepatitis and carcinoma than in control livers. The isozymes coded by different GST loci were partially purified and characterized to study their biochemical properties. The apparent Km values with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate for the isozymes at the GST1, GST2, GST3, and GST4 loci were 604, 1345, 776, and 591 microM, respectively.
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PMID:Liver glutathione S-transferase polymorphism in Japanese and its pharmacogenetic importance. 357 Feb 86

Analysis of different human tissues showed that glutathione S-transferase (GST) of fibroblasts and leucocytes is GST3, an enzyme found in liver extracts by Board (1981). Consequently, the GST localized on human chromosome 11 by Silberstein and Shows (1981, 1982) is GST3. Analysis of tissue extracts showed a new GST band, very intense in muscle extracts and very weak or absent in other tissues, and called GSTM. Analysis of man-rodent hydrids showed synteny between LDHA, GST3, ESA4 and localization of this synteny group on chromosome 11. Analysis of discordant percentages and discordant types between markers favored the following assignments: LDHA on 11p12, GST3 on 11q13 leads to 11qter, ESA on 11q13 leads to 11q22. The present study suggests assignment of GST3 to 11q13 leads to 11q22. Different types of man-rodent hybrids are useful for human gene mapping. A new type hybrid, as used here (nonadhering to glass or plastic surfaces), appears useful because of rapid proliferation and growth in suspension, the latter feature facilitating culture and harvesting.
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PMID:[Localization of the LDHA-GST3-ESA4 synthetic group on human chromosome 11. Analyses of the classic man-rodent hybrids and of a new type (not adhering to the wall)]. 660 88


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