Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thioredoxin reductase from Escherichia coli is a member of the pyridine nucleotide-disulfide oxidoreductase family, and contains one FAD and one redox-active disulfide per subunit. It is known that two other well-studied members of this family, lipoamide dehydrogenase and glutathione reductase, cycle between the two electron-reduced and fully oxidized forms in catalysis. Enzyme-monitored turnover shows that the spectrum of thioredoxin reductase during turnover represents fully reduced flavin with NADP(H) bound. Whether the pyridine nucleotide bound is NADPH or NADP+ is dependent on the concentration of each species, i.e., how far turnover has progressed. It is also shown that the midpoint potentials of this enzyme are increased through the differential binding of NADP+ to the oxidized and reduced form of the enzyme. When combined with other kinetic and oxidation/reduction studies of this enzyme, these results indicate that thioredoxin reductase cycles between the four-electron-reduced and two-electron-reduced forms in catalysis, and that it does so with pyridine nucleotide bound. These results clarify the mechanism of thioredoxin reductase in relation to the known structure the enzyme, and provide support for earlier work in which we proposed that this enzyme utilizes a ternary complex mechanism in catalysis.
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PMID:Enzyme-monitored turnover of Escherichia coli thioredoxin reductase: insights for catalysis. 866 60

The effects of anoxia and reoxygenation on major antioxidant enzyme activities were investigated in vitro in immortalized rat brain endothelial cells (RBE4 cells). A sublethal anoxic period of 12 h was assessed for RBE4 cells using the neutral red uptake test. Anoxia markedly influenced the specific activity of catalase and superoxide dismutase, with no major effect on glutathione peroxidase or glutathione reductase. After 24 h postanoxia, the superoxide dismutase activity modulated by the presence or absence of oxygen returned to control value. Damage and recovery of RBE4 immortalized rat brain endothelial cells in culture after exposure to free radicals and other oxygen-derived species provides a useful in vitro model to study anoxia-reoxygenation trauma at the cellular level.
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PMID:Effect of anoxia and reoxygenation on antioxidant enzyme activities in immortalized brain endothelial cells. 872 46

Increased exposure to oxidant-derived free radicals or inadequate systems for antioxidant defense could alter cellular response at critical points in development. We measured 5 antioxidant enzymes, glutathione peroxidase (GSH-Px), glutathione reductase, glutathione-S-transferase, catalase and superoxide dismutase in erythrocytes and their plasma cofactor trace elements (Se, Zn, Cu) in 37 children with myelomeningocele and in 37 age-matched controls. We placed the patients into 3 groups according to motor level of the lesion at birth. We found significantly lower GSH-Px activities (p = 0.007) in children with myelomeningocele. For paired comparisons among the 3 patient groups and controls, there were significant differences (p < 0.05) between controls and both high (thoracic) and raid (lumbar) level embryologic lesions. The finding of antioxidant enzyme variations in our patients with myelomeningocele may indicate a role for abnormal oxidative metabolism in the development of this defect. The contribution of oxidative stress to human birth defects warrants investigation. We discuss potential relationships between oxidative stress and energy metabolism during primary neurulation.
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PMID:Comparison of erythrocyte antioxidant enzyme activities and embryologic level of neural tube defects. 877 May 69

Heart and red blood cell endogenous antioxidant status and plasma lipids were investigated in hypertensive, 14-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats fed a standard commercial rat chow. Specific heart and red blood cell antioxidant enzyme activities, as well as the susceptibility of tissues to H2O2-induced glutathione (GSH) depletion and lipid peroxidation, were measured. Systolic blood pressure in SHR was greater than in WKY rats at 13 weeks of age (197 +/- 12 vs. 132 +/- 14 mmHg (1 mmHg = 133.3 Pa); p < or = 0.05), confirming the presence of hypertension in SHR. Red blood cell catalase (CAT) and superoxide dismutase (SOD) activities were greater (p < or = 0.05) in SHR than WKY rats. Red blood cell CAT activity was positively correlated (r = +0.634; p = 0.026) with SOD, which in turn was correlated (r = +0.709; p = 0.049) with systolic blood pressure. Heart SOD activity was higher (p < or = 0.05) in SHR, while glutathione reductase (GSSG-Red) activity was lower (p < or = 0.05) than in WKY rats. This reduced ability to recycle GSH in the heart coincided with greater (p < or = 0.05) levels of H2O2-induced lipid oxidation products in SHR. Plasma total cholesterol and triacylglycerol levels were lower (p < or = 0.05) in SHR than WKY rats, with no visible signs of atherosclerosis in either SHR or WKY rats. In summary, hypertension in SHR was associated with alterations in antioxidant enzyme profiles of red blood cells and heart, with the latter showing an increased susceptibility to in vitro lipid oxidation. Although hypertension is a recognized factor in the development of human atherosclerosis, spontaneously hypertensive rats did not exhibit signs of aortic plaque, reflecting the resistance of this species to the development of atherosclerosis.
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PMID:Heart and red blood cell antioxidant status and plasma lipid levels in the spontaneously hypertensive and normotensive Wistar-Kyoto rat. 877 9

Protein synthesis and antioxidant enzyme activities were investigated in gamma-irradiated (300 Gy) and heat shocked (42 degrees C) larval stages of the gastrointestinal parasite, Heligmosomoides polygyrus bakeri (H. polygyrus). No qualitative or quantitative differences were observed in the incorporation of (35S)-methionine into somatic proteins of unirradiated or irradiated exsheathed third-stage (L3) larvae at either 37 degrees C or 42 degrees C. The rate of protein synthesis doubled in L3 stages maintained at 42 degrees C compared with 37 degrees C, irrespective of whether the larvae had been irradiated or not. The composition of excretory/secretory (ES) proteins varied between unirradiated and irradiated exsheathed L3 larvae maintained under identical conditions. Prominent heat-inducible proteins of 26 and 17 kDa were synthesised and excreted at 42 degrees C by both unirradiated and irradiated L3 stages. No major differences in protein synthesis could be detected between unirradiated and irradiated fourth-stage (L4) larvae. Temperature elevation significantly reduced protein synthesis in L4 stages, most notably in unirradiated parasites. Heat-inducible proteins were not detected in response to either irradiation or temperature elevation in L4 larvae. Immune sera recognised a similar spectrum of antigens in both unirradiated and irradiated L4 somatic and ES preparations and reacted with antigens from irradiated L4 parasites with less intensity than with antigens from unirradiated L4 larvae. Catalase was the only antioxidant enzyme examined with activity that changed significantly in irradiated parasites, being reduced to approximately 36% of normal levels in irradiated L4 stages. No significant difference existed between irradiated and unirradiated parasites in the levels of activity of superoxide dismutase and glutathione reductase.
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PMID:The effect of gamma-radiation and heat shock on protein synthesis and antioxidant enzymes in the gastrointestinal parasite, Heligmosomoides polygyrus. 877 22

1. During all aerobic metabolism, free radicals generated by the partial reduction of oxygen are potentially injurious to cells. Highly efficient antioxidant defence systems exist to inhibit oxidative damage to cellular lipids and proteins. Specific enzymes have a crucial role in these antioxidant defences, and their activity may be induced by regulatory mechanisms that respond to oxygen metabolite concentration. 2. To assess whether smoking induces an additional adaptive response, we compared antioxidant defence systems in erythrocytes from smokers and non-smokers and assessed whether a high intake of vitamin E (280 mg/day), a major lipophilic free-radical-scavenging antioxidant, affects the activity of antioxidant enzymes. 3. A total of 100 men, 50 smokers and 50 non-smokers, were allocated to four treatment groups in a 2 x 2 factorial design (smokers versus non-smokers and placebo versus vitamin E). For 10 weeks each subject took one capsule per day of either 280 mg dl-alpha-tocopherol acetate or a visually identical placebo (hydrogenated coconut oil with negligible vitamin E content). 4. Despite increased erythrocyte cytosolic antioxidant enzyme activities in smokers compared with non-smokers, erythrocytes from smokers were more susceptible to hydrogen peroxide-induced lipid peroxidation in vitro. 5. Vitamin E supplementation further increased erythrocyte catalase (EC 1.11.1.6) activity in both smokers and non-smokers (P < 0.001) and erythrocyte glutathione peroxidase (EC 1.11.1.9) and glutathione reductase (EC 1.6.4.2) activities in non-smokers (P < 0.001). After supplementation with vitamin E there was a concomitant fall in erythrocyte superoxide dismutase (EC 1.15.1.1) activity (P < 0.001) and total glutathione concentration (P < 0.01). Furthermore, in both smokers and non-smokers there was a significant decrease in the susceptibility of erythrocytes to peroxidation (P < 0.001). 6. Various endogenous and exogenous factors exert control over cellular protection against reactive oxygen species, and our data suggest that one such factor is the supply of vitamin E.
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PMID:Effects of vitamin E supplementation on erythrocyte antioxidant defence mechanisms of smoking and non-smoking men. 877 68

It has been found that gonads of sharks contain higher content of alkoxylipids and vitamin K and lower levels of monoglycerides and carotenoids than gonads of teleost fishes. The peroxidase activity is higher in gonads of shark males but the glutathione reductase activity is lower. No significant differences in lipids peroxidation indices in gonads of elasmobranchia and teleosts were found. The total antioxidant activity of lipids in gonads of shark males exceeds 1, while the same indices of teleosts are below 1. Differences in the lipid composition, antioxidant enzyme activities, the content of glutathione, carotenoids, vitamins A, E, K and lipid peroxidation in male and female fish gonads are described. Correlation coefficients for all indices of the lipid peroxidation and antioxidant activity are estimated.
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PMID:[The ratio of processes of lipid peroxidation and antioxidant activity in gonads of Elasmobranchia and teleost fishes of the Black Sea]. 883 Apr 40

Dietary administration of the soybean isoflavone genistein (50 and 250 ppm) for 30 days significantly increases the activities of antioxidant enzymes in various organs of SENCAR mice. Feeding a 250-ppm genistein diet to SENCAR mice significantly increases the activities of catalase in small intestine, liver, and kidney, the activities of superoxide dismutase and glutathione peroxidase in skin, and the activity of glutathione reductase in skin and small intestine. Feeding 50 ppm genistein to SENCAR mice results in elevated catalase activity in the small intestine and increases glutathione-S-transferase activities in skin, small intestine, liver, kidney, and lung. Dietary genistein's greatest enhancement of antioxidant enzyme activities occurred in skin and small intestine. Our results suggest that dietary genistein enhances the activities of antioxidant enzymes in various organs, which may be a mechanism(s) of genistein's chemopreventive action.
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PMID:Effect of dietary genistein on antioxidant enzyme activities in SENCAR mice. 883 57

The mechanisms primarily responsible for the degenerative processes occurring in dystrophic skeletal muscle remain unresolved. The identification of the mechanisms that lead to the complete sparing of extraocular muscle in dystrophinopathies is of particular interest. A number of studies have provided evidence to suggest that the muscle pathology that characterizes muscular dystrophy may be, in part, free radical mediated. In the present study, we examined the antioxidant enzyme status of extraocular, diaphragm and gastrocnemius muscles in control strain and mdx mice. Our results revealed that in the control strain, both extraocular and diaphragm muscles had higher copper/zinc superoxide dismutase, manganese superoxide dismutase and selenium dependent glutathione peroxidase activities as compared to the gastrocnemius. Furthermore, the diaphragm had higher glutathione reductase activity as compared to the gastrocnemius. These findings indicate that the highly aerobic extraocular and diaphragm muscles have higher antioxidant enzyme capacity than the gastrocnemius, a muscle more dependent on anaerobic energy metabolism. Changes in the antioxidant enzyme status of the mdx mouse correlated, in part, with the degree of histopathological involvement of the three muscle groups assessed.
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PMID:Extraocular, limb and diaphragm muscle group-specific antioxidant enzyme activity patterns in control and mdx mice. 885 50

The effect of intermittent sprint cycle training on the level of muscle antioxidant enzyme protection was investigated. Resting muscle biopsies, obtained before and after 6 wk of training and 3, 24, and 72 h after the final session of an additional 1 wk of more frequent training, were analyzed for activities of the antioxidant enzymes glutathione peroxidase (GPX), glutathione reductase (GR), and superoxide dismutase (SOD). Activities of several muscle metabolic enzymes were determined to assess the effectiveness of the training. After the first 6-wk training period, no change in GPX, GR, or SOD was observed, but after the 7th week of training there was an increase in GPX from 120 +/- 12 (SE) to 164 +/- 24 mumol.min-1.g dry wt-1 (P < 0.05) and in GR from 10.8 +/- 0.8 to 16.8 +/- 2.4 mumol.min-1.g dry wt-1 (P < 0.05). There was no significant change in SOD. Sprint cycle training induced a significant (P < 0.05) elevation in the activity of phosphofructokinase and creatine kinase, implying an enhanced anaerobic capacity in the trained muscle. The present study demonstrates that intermittent sprint cycle training that induces an enhanced capacity for anaerobic energy generation also improves the level of antioxidant protection in the muscle.
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PMID:Effect of sprint cycle training on activities of antioxidant enzymes in human skeletal muscle. 890 57


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