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 far-ranging distribution of genes for aromatic hydrocarbon catabolism, predominantly studied in soil pseudomonads, is extended to a marine oligobacterium by finding five homologous sequences in a 5.7-kb chromosomal DNA from a new isolate, Cycloclasticus oligotrophus RB1. RB1 is capable of growth in unamended seawater or mineral salts media supplemented with a variety of aromatic compounds, including toluene, o-, m-, or p-xylenes, as sole carbon sources. The five open reading frames, designated xylM, K, G, C1, and C2, are 57% A+T-rich. XylM is predicted to be an integral membrane protein; XylK and XylG possess glutathione S-transferase (GST) and 2-hydroxy-5methyl-6-oxohexa2,4-dienoate dehydrogenase activities, respectively; XylC1C2 are homologs of the large and small subunits of the iron sulfur protein component of the biphenyl dioxygenase (e.g., BphA1A2).
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PMID:A marine oligobacterium harboring genes known to be part of aromatic hydrocarbon degradation pathways of soil pseudomonads. 878 14

Fruits and vegetables contain several classes of compounds that can potentially contribute to antioxidant activity, including vitamins, simple and complex phenolics, sulphur-containing compounds and glucosinolates. The glucosinolates are found in high concentration in many cruciferous vegetables, and it is well established that their breakdown products induce endogenous antioxidant defences such as quinone reductase and glutathione S-transferase in cells and in vivo. Despite the anticarcinogenic effect of these compounds in animal models, the direct antioxidant properties of this class of compounds have not been systematically studied. We therefore examined the free radical-scavenging properties of representative extracts and of purified glucosinolates from cruciferous vegetables, by measuring their effect on ascorbate- or NADPH/iron-induced peroxidation of human liver microsomes, ascorbate/iron-induced peroxidation on phospholipid liposomes, iron chelation and hydroxyl radical scavenging using the deoxyribose assay, total antioxidant potential using ABTS (2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate)) and the bleomycin assay. Most of the extracts from cruciferous vegetables exhibited some antioxidant properties, although extracts from cooked Brussels sprouts increased the rate of microsomal lipid peroxidation. The effects in these assays were dependent upon processing and species of crucifer, and the glucosinolate content appeared to play a minor role in these effects, since purified glucosinolates exhibited only weak antioxidant properties. The total antioxidant activities of extracts from cooked and autolysed Brussels sprouts were identical within experimental error. This is probably due to the content of phenolics which is unaltered by autolysis, despite the differences between these samples in other assays especially NADPH-iron-induced lipid peroxidation of human liver microsomes. The results demonstrate that glucosinolates are unlikely to account for the direct antioxidant effects of extracts from cruciferous vegetables.
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PMID:Are whole extracts and purified glucosinolates from cruciferous vegetables antioxidants? 881 45

The Rieske 2Fe-2S protein is a distinguishing subunit of the photosynthetic electron transport cytochrome b6f complex in chloroplast and cyanobacterial thylakoid membranes. We have constructed plasmids for overproduction in Escherichia coli of fusion, full-length, and truncated forms of the Rieske (PetC) protein from the cyanobacterium Nostoc sp. PCC 7906. A glutathione S-transferase/Rieske fusion protein was used to prepare specific chicken egg-yolk antibodies against the Rieske protein. Expression of the nonfusion petC gene in a T7 RNA polymerase promoter vector produced copious quantities of the full-length Rieske protein predominantly as inclusion bodies. The highly enriched, Rieske protein from inclusion bodies has been denatured in guanidine hydrochloride and refolded and the characteristic 2Fe-2S cluster reconstituted in vitro by incubation with iron and sulfide under reducing conditions. Purification by chromatography on Whatman DE52 cellulose and ultrafiltration through a 30000 molecular weight cutoff membrane yielded pure and predominantly monomeric Rieske protein. Reconstituted Rieske preparations showed intense and highly characteristic gx = 1.74, gy = 1.89, and gz = 2.03 "Rieske-type" electron paramagnetic resonance signals at 15 K. Two methods of reconstitution yielded Rieske preparations in which 20-60% of the protein contained 2Fe-2S clusters as determined by EPR spin quantitation. The reconstituted Rieske protein was soluble and stable at 4 degrees C in buffers containing nonionic detergents and showed a redox midpoint potential of +321 mV at pH 7.0 as determined by optical circular dichroism (CD) spectroscopy. These data demonstrate the in vitro restoration of a Cys and His liganded 2Fe-2S cluster and provide the basis for mutational and structural analysis of a PetC Rieske protein of oxygenic photosynthesis.
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PMID:Reconstitution of the 2Fe-2S center and g = 1.89 electron paramagnetic resonance signal into overproduced Nostoc sp. PCC 7906 Rieske protein. 895 2

Oocysts of Cryptosporidium parvum showed relatively low levels of SOD activity. The SOD which had a pI of 4.8 and an approximate molecular weight of 35 kDa appeared to be iron dependent. Catalase, glutathione transferase, glutathione reductase and glutathione peroxidase activity could not be detected, nor could trypanothione reductase. No NADH or NADPH oxidase activity could be detected, nor could peroxidase activity be demonstrated using o-dianisidine, guaiacol, NADPH or NADH as co-substrates. However, an NADPH-dependent H2O2 scavenging system was detected in the insoluble fraction.
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PMID:Anti-oxidant enzymes in Cryptosporidium parvum oocysts. 901 Oct 70

Liver lipid peroxidation, nonheme iron, antioxidants, and protein oxidation were investigated in experimental alcohol-induced liver disease in the rat. Wistar male rats were intragastrically and continuously infused for 4 weeks with a high-fat diet plus an ethanol or an isocaloric amount of dextrose, maintaining a high blood alcohol level (200-300 mg%). This model induced fatty liver, spotty necrosis, and focal inflammation. This pathology was associated with an enhanced lipid peroxidation and a decrease in the major antioxidant factors. Hepatic alpha-tocopherol and glutathione concentrations were significantly decreased in ethanol-fed rats. Glutathione peroxidase (GPx) was also decreased, whereas glutathione S-transferase (GST) was unaffected. The nonheme iron level was significantly decreased. Protein oxidation was assessed through three parameters: protein thiols, protein carbonyl groups, and the activity of glutamine synthetase (GS), a centrilobular enzyme particularly susceptible to free-radical-mediated damage. Ethanol-fed rats had decreased protein thiol concentrations and reduced GS activity, together with increased protein carbonyls. A significant correlation between GS activity and the pathological score was observed. This study confirms the ethanol-related increase in lipid peroxidation and shows that ethanol impairs the hepatic antioxidant potential. Furthermore, evidence of oxidative protein damage is given, including decreased activity of a key enzyme of ammonia metabolism. These protein disturbances may contribute to the pathogenesis of the observed liver damage.
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PMID:Effect of chronic ethanol feeding on lipid peroxidation and protein oxidation in relation to liver pathology. 902 46

Diethylnitrosamine (DEN) was administered to rats as a single dose, which is known not to give rise to liver tumours without subsequent promotion. Iron dextran (Fe/Dex) was then administered parenterally to the animals, to induce iron overload. At 3 and 6 months after the final Fe/Dex treatments, livers were examined quantitatively for the numbers of the placental form of glutathione-S-transferase (GST-P) expressing foci, the area occupied by these foci and their size distribution. The results demonstrate that iron not only increased the number of foci after DEN initiation in the rat liver, but that the area occupied by these lesions increased significantly between 3 and 6 months after initiation. There is no evidence that iron increased the number of GST-P expressing foci present in rats not exposed to DEN. This indicates that iron did not act as an initiator in this rodent model of liver cancer. The increase in the area of the liver occupied by the foci in iron and DEN treated rats was due to an increase in the size of the foci, as well as to an increase in the number of foci. This is the first demonstration that iron can act as a promoter of DEN initiated hepatocytes. It also demonstrates that fibrogenesis is not an absolute requirement for the promotion, by iron, of liver foci in the rat, and that this could also be the case for iron overload in man. Iron may also act as a promoter of already initiated hepatocytes in the development of human liver cancer, as it does in the rat.
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PMID:Iron promotes DEN initiated GST-P foci in rat liver. 906 62

We have expressed, purified, and analyzed the iron-containing superoxide dismutase (FeSOD) of Escherichia coli with mutations directed at tyrosine position 34 to introduce phenylalanine (SODY34F), serine (SODY34S), or cysteine (SODY34C). FeSOD and mutant enzymes were purified from SOD-deficient cells using a GST-FeSOD fusion protein intermediate which was subsequently cleaved with thrombin and repurified. Specific activities were measured using the xanthine-xanthine oxidase method and gave 3148 u/mg for wild-type FeSOD. The SODY34S mutation virtually inactivates the enzyme (42 u/mg); mutation to cysteine greatly reduces activity (563 u/mg), but the SODY34F mutant retains nearly 40% of the activity of wild type (1205 u/mg). Fusion protein intermediates were also shown to be active and were demonstrated to protect SOD-deficient E. coli cells from the induced effects of oxidative stress, with growth rates directly proportional to the specific activities of the expressed mutant enzymes. SODY34F exhibited decreased thermal stability, reduced activity at high pH, and a pronounced increase in sensitivity to the inhibitor sodium azide compared with wild-type FeSOD. These results suggest that tyrosine at position 34 is multifunctional and plays a structural role (probably through hydrogen bonding to glutamine at position 69) in maintaining the integrity of the active site, a stabilizing role at high pH, and a steric role in obstructing access to the active site of both substrate and inhibitor molecules.
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PMID:The conserved residue tyrosine 34 is essential for maximal activity of iron-superoxide dismutase from Escherichia coli. 912 14

Hypothetical, therapeutic effects of ozone were investigated in an animal model. One ml of oxygen or mixture of 40 micrograms ozone with oxygen were injected intraperitoneally to male rats for 10 days. Previously, rats had been poisoned with 50 ppm Cd2+ in drinking water for 12 weeks. Exhaustive treadmill running was applied to some animals before sacrification. Ozone injections increased iron-ascorbate-stimulated lipid peroxidation (LPO) in the liver and kidney, catalase (CAT) activity in the heart and glutathione S-transferase (GST) activity in the heart, kidney and liver. Oxygen increased GST activity in the brain and reduced glutathione peroxidase (GPX) activity in the kidney. Cadmium enhanced LPO in the liver and GST activity in the brain, heart, kidney and liver. In contrast to ozone, cadmium inhibited GPX activity in the brain, kidney and liver. Cadmium combined with ozone enhanced the changes of GPX activity in the kidney and liver, that of GST activity in the heart, kidney and liver as well as of CAT activity and LPO in kidney. The results suggest that ozone injections combined with tested factors may provoke an oxidative stress. The effects of ozone therapy can not be explained as the results of ozone action on the antioxidative enzymes in rat.
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PMID:Lipid peroxidation and activity of antioxidative enzymes in the rat model of ozone therapy. 930 39

The binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with the aryl hydrocarbon (AH) receptor and subsequent changes in gene expression have been studied intensively, but the mechanisms by which these lead to toxicity are unclear. We investigated the influence of iron, previously implicated in TCDD-induced hepatic porphyria, in mice with alleles of Ahr that encode receptors with varied affinity for TCDD. The administration of iron to Ahrb-1 C57BL/6J (AH-responsive) mice before a single dose of TCDD (75 micrograms/kg) markedly potentiated not only the hepatic porphyria but also general hepatocellular damage and elevation of plasma hepatic enzymes. The formation of hydroxylated and peroxylated derivatives of uroporphyrins formed from uroporphyrinogen and the induction of a mu-glutathione transferase (GST) were consistent with the operation of an oxidative mechanism. In a comparison of C57BL/6J mice with Ahrb-2 BALB/c (AH-responsive) and Ahrd SWR and DBA/2 (AH-nonresponsive) mice, iron overcame the weak hepatic porphyria and toxicity responses in BALB/c and SWR strains but not in DBA/2. CYP1A isoforms are strongly implicated in the mechanism of porphyria, but activities were lowered by 20-30% with iron treatment, and a comparison of levels between strains did not fully account for the resistance of DBA/2 mice. Studies with the use of gel shift assays and cytosolic aconitase of the capacity of the iron regulatory protein controlling the translation of some iron metabolism proteins showed a significant difference between C57BL/6J and DBA/2 mice after the administration of TCDD. We conclude that iron potentiates both the hepatic porphyria and toxicity of TCDD in susceptible mice in an oxidative process with disturbance of iron regulatory protein capacity. Iron even overcomes the AH-nonresponsive Ahrd allele in the SWR strain but not in DBA/2 mice, which remain resistant.
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PMID:Interaction between iron metabolism and 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice with variants of the Ahr gene: a hepatic oxidative mechanism. 944 32

It has been suggested that high iron stores enhance colon carcinogenesis. The effect of high dietary iron (Fe) on indices of iron, copper (Cu) and manganese (Mn) status, lipid peroxidation using the thiobarbituric acid reactive substances assay, superoxide dismutase, glutathione peroxidase, glutathione transferase and ceruloplasmin activities, cell proliferation and development of preneoplastic lesions known as aberrant crypt foci (ACF) in rat colon was examined using a 3 x 2 factorial design. Male weanling Sprague-Dawley rats were fed adequate (AFe; 45 mg Fe/kg diet), moderately high (MHFe; 225 mg Fe/kg diet) and high (HFe; 450 mg Fe/kg diet) dietary Fe for 2.5 wk, then treated with azoxymethane (AOM; 2 injections, 1 wk apart; total dose 30 mg/kg body weight) or saline (n = 14-15 per group). Dietary treatment continued for another 6 wk after the second AOM dose. At the time of AOM injection, colon Fe concentrations were one- and threefold higher for MHFe and HFe rats, respectively, than for AFe rats. It was proposed that high dietary Fe would adversely affect Cu and Mn status, resulting in impaired antioxidant enzyme activity. However, neither indices of Cu and Mn status nor colonic mucosal antioxidant enzyme activities were affected by dietary Fe except for plasma ceruloplasmin activity, which was slightly lower in rats fed high iron diets than in rats fed adequate iron diets (P < 0.01). Dietary Fe had no significant effect on colonic mucosal lipid peroxidation, cell proliferation or ACF development. In conclusion, our findings suggest that dietary Fe concentrations that are approximately 5 and 10 times adequate do not enhance oxidative stress, cell proliferation and ACF development in the colon of rats.
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PMID:Iron supplementation does not affect cell proliferation or aberrant crypt foci development in the colon of sprague-dawley rats. 952 41


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