Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.6 (catalase)
 55,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The disulfide-sulfhydryl ratio of rat hepatic tissue has been found to vary diurnally lowest in the early morning and highest in the early evening (Isaacs, J. (1976) Fed. Proc. 35, 1472, and Isaacs, J. and Binkley, F. (1977) Biochim. Biophys. Acta 497, 192-204). Intraperitoneal injections of dibutyryl cyclic AMP induces an increase in hepatic glutathione protein mixed disulfides (GSSProt) combined with a corresponding decrease in reduced glutathione (GSH) and protein sulfhydryl (ProtSH). Also, dibutyryl cyclic AMP caused hepatic catalase activity to decrease and to increase hepatic production of peroxide molecules. A decrease in catalase activity directs more of the increased peroxide into the glutathione peroxidase pathway. This leads to increased amounts of oxidized glutathione (GSSG) which ultimately results in increased levels of GSSProt. Therefore cyclic AMP may mediate its effect on the disulfide-sulfhydryl ratio via control over catalase and peroxide generation. Support for this idea is provided by the close temporal correlation between the diurnal variations in cyclic AMP, hepatic catalase, peroxide generation and GSSProt-GSH levels.
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PMID:Cyclic AMP-dependent control of the rat hepatic glutathione disulfide-sulfhydryl ratio. 1 7

Oxidation of methanol, formaldehyde and formic acid was studied in cells and cell-free extract of the yeast Candida boidinii No. 11Bh. Methanol oxidase, an enzyme oxidizing methanol to formaldehyde, was formed inducibly after the addition of methanol to yeast cells. The oxidation of methanol by cell-free extract was dependent on the presence of oxygen and independent of any addition of nicotine-amide nucleotides. Temperature optimum for the oxidation of methanol to formaldehyde was 35 degrees C, pH optimum was 8.5. The Km for methanol was 0.8mM. The cell-free extract exhibited a broad substrate specificity towards primary alcohols (C1--C6). The activity of methanol oxidase was not inhibited by 1mM KCN, EDTA or monoiodoacetic acid. The strongest inhibitory action was exerted by p-chloromercuribenzoate. Both the cells and the cell-free extract contained catalase which participated in the oxidation of methanol to formaldehyde; the enzyme was constitutively formed by the yeast. The pH optimum for the degradation of H2O2 was in the same range as the optimum for methanol oxidation, viz. at 8.5. Catalase was more resistant to high pH than methanol oxidase. The cell-free extract contained also GSH-dependent NAD-formaldehyde dehydrogenase with Km = 0.29mM and NAD-formate dehydrogenase with Km = 55mM.
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PMID:Studies on methanol - oxidizing yeast. III. Enzyme. 24 Jul 64

It seems that superoxide dismutase plays the key role in protecting aerobes against O2 toxicity, but there is a whole range of ancillary mechanisms: enzymes to remove H2O2 (catalase, peroxidases) and hence to control formation of .OH from O2, which requires H2O2; antioxidants (ascorbate, GSH, alpha-tocopherol, carotenoids), which also react with singlet oxygen and/or .OH and often inhibit lipid peroxidation and last, but not least in animals, glutathione peroxidase, which controls the rate of lipid peroxidation. These mechanisms cope well at normal O2 concentrations but are insufficient at higher levels.
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PMID:Biochemical mechanisms accounting for the toxic action of oxygen on living organisms: the key role of superoxide dismutase. 35 40

The present knowledge of glutathione (GSH) peroxidase is briefly reviewed: GSH peroxidase has a molecular weight of about 85,000, consists of four apparently-identical subunits and contains four g atom of selenium/mol. The enzyme-bound selenium can undergo a substrate-induced redox change and is obviously essential for activity. In accordance with the assumption that a selenol group is reversibly oxidized during catalysis, ping-pong kinetics are observed. Limiting maximum velocities and Michaelis constants, indicating the formation of an enzyme-substrate complex, are not detectable. The enzyme is highly specific for GSH but reacts with many hydroperoxides. It can be deduced from the kinetic analysis of GSH peroxidase that in physiological conditions removal of hydroperoxide is largely independent of fluctuations in the cellular concentration of GSH. However, the system will abruptly collapse if the rate of hydroperoxide formation exceeds that of regeneration of GSH. By these considerations, the pathophysiological manifestation of disorders in GSH metabolism and pentose-phosphate shunt may be explained. With regard to its low specificity for hydroperoxides, GSH peroxidase could be involved in various metabolic events such as H2O2 removal in compartments low in catalase, hydroperoxide-mediated mutagenesis, protection of unsaturated lipids in biomembranes, prostaglandin biosynthesis, and regulation of prostacyclin formation.
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PMID:Glutathione peroxidase: fact and fiction. 38 23

The effects of various levels of selenium, alpha-tocopherol and sulfur on glutathione peroxidase (GSH-Px) activity in intestinal and liver tissues were determined in male rats fed corn-soybean or Torula yeast diets. Rats fed corn-soybean diets had greater GSH-Px activity in the small intestine, colon and liver tissues, catalase activity and selenium in the liver, and body weight gains than those fed Torula yeast diets. GSH-Px activity in the small intestine, colon, and liver tissues as well as concentration of selenium in the liver increased with increasing levels of selenium in Torula yeast diets but not with corn-soybean diets. Tocopherol supplementation had no significant effect on GSH-Px activity in rats fed Torula yeast or corn-soybean diets supplemented with selenium. Supplemental sulfur decreased GSH-Px activity in the small intestine tissues and increased activity in colon tissues.
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PMID:Glutathione peroxidase acitvity in intestinal and liver tissues of rats fed various levels of selenium, sulfur and alpha-tocopherol. 43 Feb 45

The effect of dietary selenium and vitamin E on the important cellular antioxidant defense systems was studied in rat erythrocytes. Weanling male Sprague-Dawley rats were fed a basal selenium and vitamin E deficient diet and supplemented with either none or 0.5 ppm selenium and either none or 45 ppm vitamin E for 35 or 40 days. Depletion of dietary selenium resulted in marked decrease of glutathione (GSH) peroxidase in the red cells, but the levels of GSH, catalase and superoxide dismutase were not significantly altered. The red cells of rats fed the basal diet deficient in both selenium and vitamin E had significantly lower levels of GSH and GSH peroxidase, but not of catalase and superoxide dismutase, than in those fed the basal diet and supplemented with either selenium, vitamin E or both. The results suggest that depletion of dietary selenium and vitamin may have a precipitate effect on lowering the levels of GSH and GSH peroxidase in rat erytyrocytes.
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PMID:Effect of dietary selenium and vitamin E on the antioxiant defense systems of rat erythrocytes. 46 73

Chlorine dioxide (Cl02) has been proposed as an alternative disinfectant to chlorine to avoid formation of organohalides. Cl02 and metabolites, chlorite (Cl0-2) and chlorate (Cl0-3) in drinking water produced decreases in rat and chicken blood GSH. The GSH dependent system was studied in rat and chicken blood after chronic treatment for 6 months with CL02 (0, 1, 10, 100, 1000 MG/L), Cl0-2 or Cl0-3 (10, 100 mg/l) in drinking water. There was a 60% increase in GSH reductase in the Cl02 treatment groups of rats and chickens. A similar increase was shown in rats treated with Cl0-2 but with Cl0-3 no change was observed. GSH peroxidase was without change in rat but chickens drinking 1000 mg/l Cl02 had decreased activity. Catalase was significantly higher than control in rat and chicken in the 1000 mg/l groups. However, catalase activity was decreased in rat treated with Cl0-2 and at the same time that GSH was decreased. These studies support the view that catalase is the first line of defense against the oxidative stress of Cl02 in rat and chicken erythrocytes.
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PMID:Effect of chlorine dioxide and metabolites on glutathione dependent system in rat, mouse and chicken blood. 54 25

The activities of catalase (E.C.1.11.1.6) and glutathione peroxidase (E.C.1.11.1.9) were compared in red blood cells from humans, ducks and normal and acatalasemic mice. In the cells from both strains of mice, an equally high activity of GSH-Px was found which could be inhibited completely by iodoacetate but was not sensitive to N-ethylmaleimide.
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PMID:A highly active glutathione peroxidase in red blood cells of normal and acatalasemic mice. 59 Apr 40

The formation of glutathione radicals, the evolution of nascent oxygen or the peroxidatic reaction with catalase complex I are considered as possible mechanisms for the oxidation of mercury vapor by red blood cells. To select among these, the uptake of atomic mercury by erythrocytes from different species was studied and related to their various activities of catalase (hydrogenperoxide : hydrogen-peroxide oxidoreductase, EC 1.11.1.6) and glutathione peroxidase (glutathione : hydrogen-peroxide oxidoreductase, EC 1.11.1.9). A slow and continuous infusion of diluted H2O2 was used to maintain steady concentrations of complex I. 1% red cell supsensions were found most suitable showing high rates of Hg uptake and yielding still enough cells for subsequent determinations. The results indicate that the oxidation of mercury depends upon the H2O2-generation rate and upon the specific acticity of red-cell catalase. The oxidation occurred in a range of the catalase-H2O2 reaction where the evolution of oxygen could be excluded. Compounds reacting with complex I were shown to be effective inhibitors of the mercury uptake. GSH-peroxidase did not participate in the oxidation but rather, was found to inhibit it by competing with catalase for hydrogen peroxide. These findings support the view that elemental mercury is oxidized in erythrocytes by a peroxidatic reaction with complex I only.
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PMID:Enzymatic oxidation of mercury vapor by erythrocytes. 65 39

Activities of catalase (H2O2: H2O2 oxidoreductase, EC 1.11.1.6) and GSH peroxidase (GSH: H202 oxidoreductase, EC 1.11.1.9) have been measured in iris, ciliary body, retina, corneal epithelium, corneal endothelium, lens capsule-epithelium and decapsulated lens. 3-Amino-1H-1,2,4-triazole is a specific inhibitor of catalase and a potent cataractogenic agent. We observed marked inhibition of catalase activity in these tissues 1--6 h after the administration of a single intravenous dose of 1 g 3-aminotriazole per kg body weight in rabbit. This was associated with a 2--3-fold increase in the H2O2 concentrations of aqueous humor and vitreous humor. The increased peroxide concentrations were restored to the physiological levels as the catalase activity of eye tissues gradually returned to normal with time after injection. Under the conditions, GSH peroxidase activity of the afore-mentioned eye tissues was unaltered, GSH and protein sulfhydryl of lens were not changed, and ascorbic acid of aqueous humor and vitreous humor was not significantly altered. Based on these findings our conclusion is that catalase of eye tissues regulates the endogenous H2O2 in eye humors to the physiological level. We speculate that H2O2 may be the triggering factor in cataract induced by 3-aminotriazole.
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PMID:Regulation of hydrogen peroxide in eye humors. Effect of 3-amino-1H-1,2,4-triazole on catalase and glutathione peroxidase of rabbit eye. 88 79


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