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)

We describe a rapid kinetic method for the automated determination of the xenobiotic-metabolizing enzymes glutathione reductase, glutathione peroxidase and glutathione S-transferase, and its application to the study of cisplatin-induced toxicity. Liver, kidney and urine from control and cisplatin-treated rats were used as the source of enzymes. Advantages over conventional spectrophotometric methods include speed (25 assays in 4 min), small sample size, and improved precision. We show that glutathione S-transferase activity in liver is slightly reduced by cisplatin treatment, whereas all three enzymes are reduced in the kidney. Glutathione-S-transferase activity appeared in urine between the third and seventh days after cisplatin injection. Using these enzyme activities in cisplatin-treated rats, we suggest that the renal enzymes are more sensitive markers of toxicity than hepatic enzymes.
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PMID:Rapid automated analysis of glutathione reductase, peroxidase, and S-transferase activity: application to cisplatin-induced toxicity. 228 7

The effects of prolonged dietary administration of peroxisome proliferators, such as clofibrate, bezafibrate and di(2-ethylhexyl)phthalate (DEHP), on hepatic hydrogen peroxide (H2O2) level and on hepatic activities of the enzymes relating to H2O2 metabolism were examined. Male rats were treated for 79 weeks with the above three peroxisome proliferators. The activities of the peroxisomal beta-oxidation and catalase were increased 8- to 20-fold and 2- to 3-fold, respectively, after 2 or 4 weeks of treatment with these peroxisome proliferators. However at 79 weeks the peroxisomal beta-oxidation activity was 3-8 times that of control. The level of catalase activity was kept at approximately 2-fold even after prolonged treatment of peroxisome proliferators. Although the activities of glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST) were decreased 50-60% at 4-12 weeks by the treatment with peroxisome proliferators, from 20 to 79 weeks those activities approached control levels in the case of clofibrate and bezafibrate but not DEHP-fed rats; GSH-Px and GST activities were kept at approximately 40% those of control. However hepatic capacities of H2O2-degrading enzymes, catalase and GSH-Px, apparently exceeded the H2O2-generating levels obtained on the basis of peroxisomal beta-oxidation activities in the livers of control and treated rats throughout the experimental period. The hepatic H2O2 levels increased only slightly but this increase did not correspond to changes in peroxisomal beta-oxidation. Our results suggest that a large part of H2O2 produced by peroxisomal beta-oxidation could be rapidly scavenged by catalase and GSH-Px in the liver of rats treated with peroxisome proliferators.
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PMID:Long-term effects of hypolipidemic peroxisome proliferator administration on hepatic hydrogen peroxide metabolism in rats. 231 Nov 88

Glutathione S-transferases play a central role in drug detoxification and have been implicated in the sensitivity of tumour cells to anticancer drugs. In this study, glutathione S-transferase (GST) isozyme expression in normal and tumour tissue from human lung, colon, stomach, breast, kidney and liver tissue has been quantified using sensitive and subunit specific radioimmunoassays (RIA), together with Western blot analysis and measurement of substrate metabolism. Glutathione S-transferase pi was the predominant GST in the majority of the tumours examined. The concentration of this enzyme was increased significantly in tumour tissue relative to normal lung, colon, and stomach tissue. A strong correlation was observed (r = 0.77, P less than 0.01) between GST activity and GST pi levels in those tumour samples. The concentrations of the alpha class GST, the predominant isoenzymes in normal stomach, kidney and liver, decreased dramatically in tumour tissue from these organs. Western blot analysis revealed the presence of novel polypeptides that cross-reacted with antisera raised against alpha and mu class GST. Our data demonstrates that although GST pi is the predominant GST isoenzyme in many tumours, significant levels of the other GST subunits are also present and collectively can represent a significant proportion of the GST content. Therefore the properties of all the GST isoenzymes need consideration when assessing the role of these proteins in drug resistance. Selenium-dependent glutathione peroxidase, an enzyme activity also implicated in the mode of action of certain antitumour agents, was also studied and shown to be the predominant glutathione-dependent peroxidase in all tumours except the hepatoma.
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PMID:Glutathione S-transferase and glutathione peroxidase expression in normal and tumour human tissues. 231 Nov 89

The activities of glutathione peroxidase (GSH-px), glutathione reductase (GSSG-rx) and glutathione transferase (GST) were measured in myocardial specimens obtained from right atria of patients subjected to different period of ischaemic arrest (aortic clamping ranging from 10 min to 90 min) followed by 60 min. of reperfusion, during open heart surgery 41-90 min. period of aortic clamping induced a significant increase of GSH-px activity with both H2O2 (p less than 0.05) and cumene hydroperoxide (p less than 0.025) as substrates when compared with baseline levels. Aortic clamping and reperfusion, however did not significantly change the myocardial activities of glutathione transferase and glutathione reductase. It is suggested that the increase of GSH-px in ischaemic-reperfused human hearts may render the myocardium less susceptible to oxidative attack particularly during the reoxygenation period when the level of active oxygen species is greatly elevated.
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PMID:Effect of ischaemia-reperfusion on glutathione peroxidase, glutathione reductase and glutathione transferase activities in human heart protected by hypothermic cardioplegia. 231 22

In 24 rabbits fed a hyperlipidic diet (0.5% cholesterol, 5% lard and 5% peanut oil) for 10 (group A1), 30 group B1) and 60 days, (Group C1), compared to 24 control rabbits fed a standard diet for the same periods, antioxidant defence system (total superoxide dismutase, catalase, total thiol compounds selenium-dependent and selenium-independent glutathione peroxidase, glutathione reductase, glutathione transferase) and lipid peroxidation (thiobarbituric acid-reactive substances) in the aortic wall were tested. The percent of intima with grossly apparent atherosclerosis, is assessed by staining with the lipophilic dye Sudan IV, was negligible in group A1, but increased progressively in groups B1 (22.7-6.7%) and C1 (56.8-8.8%). Compared to the controls, a significant rise in superoxide dismutase activity was observed after 30 days of hyperlipidic diet, with a further marked increase at 60 days. Total thiol compounds and selenium-dependent glutathione peroxidase activity rose progressively from 10 to 30 and 60 days in cholesterol-fed rabbits. On the contrary, catalase, glutathione reductase and glutathione transferase activities significantly decreased in all experimental groups. Selenium-independent glutathione peroxidase activity was not detectable. Thiobarbituric acid-reactive substances increased about 3 times in hyperlipidemic rabbits. In conclusion, the changes in aortic antioxidant defence mechanisms and lipid peroxidation precede the massive vascular lipid infiltration in cholesterol-fed rabbits; some antioxidant mechanisms are stressed (superoxide, dismutase, glutathione peroxidase, total thiol compounds), whereas others are depressed (catalase, glutathione reductase, and glutathione transferase), thus potentially reducing or increasing vascular susceptibility to oxidative injury.
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PMID:Aortic antioxidant defence mechanisms: time-related changes in cholesterol-fed rabbits. 232 23

Four types of glutathione S-transferase were purified to homogeneity from guinea pig liver by DEAE-cellulose, Sephadex G-75, CM-cellulose, and affinity chromatography. These isozymes were named a, b, c, and d based on the reverse order of elution from a CM-cellulose column, and had specific activities of 89.6, 92.2, 99.0, and 44.0 units/mg, respectively, when assayed with 1 mM each of 1-chloro-2,4-dinitrobenzene and reduced glutathione. All four transferases of guinea pig liver were homodimers. The transferases b, c, and d had a similar molecular weight of 50,000 and their subunit sizes were 25,000, but the corresponding values for transferase a were 45,000 and 23,500, respectively. Transferase a was notably different in the activities towards organic hydroperoxides and 1,2-dichloro-4-nitrobenzene from the other isozymes. Transferases a and b, the major forms in guinea pig liver, were studied with respect to their biochemical properties, including kinetic parameters, absorption and fluorescence spectra, and bilirubin binding. Glutathione peroxidase activity of the transferase a was about 100 times higher than that of other isozymes. In guinea pig liver, it is estimated that transferase a is the major glutathione peroxidase, accounting for about 75% of the total organic hydroperoxide reduction.
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PMID:Purification and characterization of glutathione S-transferases from guinea pig liver. 233 12

As many as 160 patients with acute virus hepatitis B (AVHB) were examined over time. Spectroscopy was used to study the activity of glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase-1 (GP1), glutathione peroxidase-2 (GP2), glutathione reductase (GR), glutathione transferase (GT) and to measure the concentration of reduced glutathione (GSH) in the blood serum and in red blood cells. Within the first days of the icteric period, the activity of all the enzymes rose, followed by reduction of the activity of G-6-PDH, GP1, GP2, GR and the concentration of GSH at the height of the disease. The GT activity remained high throughout the entire disease period.
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PMID:[The functioning of the glutathione system in patients with acute viral hepatitis B]. 233 29

Transfection of a human pSV2 (copper-zinc) superoxide dismutase expression vector into murine fibroblasts resulted in stable clones producing increased amounts of copper-zinc superoxide dismutase. A marked increase in endogenous glutathione peroxidase activity (up to 285%) and a smaller increase in glutathione transferase activity (up to 16%) also occurred. Manganese superoxide dismutase activity was decreased in all clones, whereas catalase and NADPH reductase activities were not affected. Alterations in glutathione peroxidase and manganese superoxide dismutase activities correlated with increases in copper-zinc superoxide dismutase activity. Whereas all clones were resistant to paraquat, a direct correlation between copper-zinc superoxide dismutase activity and resistance to paraquat did not exist. In agreement with previous reports clones expressing the highest copper-zinc superoxide dismutase activity did not display the highest resistance to paraquat. However, there was a direct correlation between the increase in glutathione peroxidase activity and paraquat resistance (p less than 0.002).
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PMID:Alteration of endogenous glutathione peroxidase, manganese superoxide dismutase, and glutathione transferase activity in cells transfected with a copper-zinc superoxide dismutase expression vector. Explanation for variations in paraquat resistance. 235 46

Glutathione S-transferase located in outer mitochondrial membrane was purified from rat liver into homogeneous state on SDS-PAGE by two steps of chromatography. Outer mitochondrial membrane glutathione S-transferase was immunochemically related with microsomal glutathione S-transferase and shared similar characteristics each other, e.g., stimulation of the activity by treatment with N-ethylmaleimide, molecular weight, optimal pH, substrate specificities, glutathione peroxidase activity, kinetic parameters, amino acid composition and profile of peptide mapping by protease.
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PMID:Purification and properties of glutathione S-transferase from outer mitochondrial membrane of rat liver. 236 11

A glutathione peroxidase was purified from bovine ciliary body by ammonium sulfate fractionation. Sephacryl S-300 gel filtration, diethylaminoethyl (DEAE)-cellulose chromatography and hydroxyapatite chromatography. The purified enzyme has an apparent mw of 112 kDa by gel filtration and 29 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme therefore is composed of four identical subunits. The ciliary enzyme is active with H2O2 (25), cumene hydroperoxide (170), t-butyl hydroperoxide (22), triphenylcarbinyl hydroperoxide (12), linoleic hydroperoxide (34) and 5-phenylpentenyl hydroperoxide (22): the numbers after substrates are K'm in microM. Glutathione is essential for the reaction; L-cysteine, dithiothreitol and 2-mercaptoethanol are inactive. Mercaptosuccinate (10 microM) inhibits the enzyme competitively (Ki = 7 microM) when cumene hydroperoxide is substrate, and uncompetitively (Ki = 10 microM) when H2O2 is substrate. No selenium was found in the enzyme by the fluorometric assay with 2.3-diaminonaphthalene. The enzyme demonstrates no glutathione S-transferase activity when tested with 1-chloro-2,4-dinitrobenzene, and several other compounds. A partial sequence of the enzyme shows some similarities both to Se-glutathione peroxidases and a glutathione S-transferase isozyme.
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PMID:Non-selenium glutathione peroxidase without glutathione S-transferase activity from bovine ciliary body. 237 54


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