Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ascorbate caused a dose-dependent increase in sister-chromatid exchanges (SCEs) in Chinese hamster ovary (CHO) cells and in human lymphocytes. Moreover, in the DNA synthesis inhibition test with HeLa cells, ascorbate gave results typical of DNA-damaging chemicals. Catalase reduced SCE induction by ascorbate, prevented its cytotoxicity in CHO cells, and prevented its effect on HeLa DNA synthesis. Ascorbate reduced induction of SCE in CHO cells by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) by direct inactivation of MNNG.
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PMID:Vitamin C is positive in the DNA synthesis inhibition and sister-chromatid exchange tests. 48 30

A fully enzymatic method to determine total cholesterol in serum is described. The method appears especially suitable for adaptation to discrete mechanical analyzers either of the single channel or the multi-channel type. The method uses the enzymes cholesterol esterase (EC 3.1.1.13), cholesterol oxidase (EC 1.1.3.6) and peroxidase (EC 1.11.1.7) with 4-aminophenazone and phenol as substrates in the indicator reaction. The method was adapted to the Greiner Selective Analyzer GSA-II. For this purpose the critical parameters of the reaction were intensively examined. The complete reagent is stable within the GSA II dispenser at 4 degrees C for at least 1 week. By omitting cholesterol oxidase in the blank reagent a sample bland and a partial reagent blank are obtained. Within a range up to 10.4 mmol/1 (4.0 g/l) the maximum colour is developed within 6 minutes. The calibration factor was stable for 4 months. The method allows absolute measurements. At concentrations between 2 and 4 mmol/1 within-batch precision ranged from 0.5 to 1.4%. Precision from day to day for the same control sera amounted to 2.8; 2.0; 2.7 and 2.0% for a period of 3 months. Examination of accuracy yielded satisfying results. Ascorbic acid in the physiological range did not alter results to a significant extent. Catalase or novaminesulfone added in vitro did not interfere. Optical interferences by bilirubin, hemoglobin or turbidity are compensated by a sample blank. A comparison of results with the enzymatic method of Roeschlau et al. (Z. Klin. Chem. Klin. Biochem. 12, 226 (1974)) yielded satisfactory agreement. The limits of detection of the present method can be lowered by a factor of 2.2 by replacing phenol by dihalogen phenols.
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PMID:[Enzymatic determination of total cholesterol with the Greiner Selective Analyzer (GSA-II) (author's transl)]. 87 Jun 10

Oxidative stress responses were tested in the unicellular cyanobacterium synechococcus PCC 7942 (R-2). Cells were exposed to hydrogen peroxide, cumene hydroperoxide and high light intensities. The extent and time course of oxidative stress were related to the activities of ascorbate peroxidase and catalase. Ascorbate peroxidase was found to be the major enzyme involved in the removal of hydrogen peroxide under the tested oxidative stress. Catalase activity was inhibited in cells, treated with high H2O2 concentrations, and was not induced under photooxidative stress. Catalase was specifically induced in cells treated with cumene hydroperoxide. Superoxide dismutase activity increased under conditions generating superoxide, such as high light intensities. The induction of the antioxidative enzymes was light dependent and was inhibited by chloramphenicol.
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PMID:Oxidative stress responses in the unicellular cyanobacterium Synechococcus PCC 7942. 190 71

This study has investigated the kinetics and mechanism of ultraweak luminescence in maize roots. Mannitol induced the second maximum and enhanced the main maximum of the relative intensity of luminescence from the roots. Hydroquinone and quinone enhanced the relative intensity of the luminescence. Catalase enhanced the maximum of the luminescence and changed the kinetics of the light emission. The effect of catalase on the kinetics was abolished by superoxide dismutase. Ascorbate in the presence of catalase on the kinetics was abolished by superoxide dismutase. Ascorbate in the presence of catalase reduced the luminescence maximum, but did not alter the kinetics. In the presence of catalase only, or in the combination with superoxide dismutase, or ascorbate, the luminescence intensity in the stationary phase was significantly lower compared to the control. The results support the participation of superoxide-radical, singlet oxygen, electron transfer and the role of peroxidase in the reactions generating ultraweak luminescence in the roots. Ascorbate, catalase and superoxide dismutase have a protective role in the luminescent reactions.
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PMID:Effect of propagators and inhibitors on the ultraweak luminescence from maize roots. 217 39

Hemin (ferric protoporphyrin IX chloride) in the presence of hydrogen peroxide or tert-butyl hydroperoxide was found to cleave folic acid at the C9-N10 bond. The ferrous form of hemin was not involved in hydroperoxide-dependent folic acid degradation, as indicated by the lack of inhibition by carbon monoxide. Molecular oxygen was not required for the degradation. GSH-Mn(II) or NAD(P)H in the presence of molecular oxygen did not support hemin-mediated folic acid degradation. The degradation increased as the temperature was elevated from 10 to 70 degrees C. Ascorbic acid and azide were potent inhibitors. Superoxide dismutase and hydroxyl radical quenchers, such as ethanol, mannitol, benzoate, and dimethyl sulfoxide did not inhibit the reaction. Catalase inhibited hydrogen peroxide-supported degradation but not the tert-butyl hydroperoxide-dependent one. Thiol compounds, such as thioglycolic acid, thiourea, glutathione, cysteine, and 2-mercaptoethanol, inhibited the hydrogen peroxide-dependent degradation but supported the tert-butyl hydroperoxide-mediated one. N5-formyl tetrahydrofolic acid, but not N10-formyl folic acid, was degraded by hemin in the presence of H2O2 or TBHP. The data obtained are suggestive of a mechanism similar to N-demethylation reactions catalyzed by cytochrome P-450 and some peroxidases.
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PMID:Studies on hydroperoxide-dependent folic acid degradation by hemin. 282 Mar 6

Photoemissive excited species are produced by the horseradish peroxidase (HRP)-catalyzed oxidation of reduced glutathione (GSH), without exogenously added hydroperoxide under aerobic conditions. The emitted low-level chemiluminescence consisted of two phases. Light emission occurred at wavelengths beyond 610 nm (greater than or equal to 90% intensity), indicative of singlet oxygen 1O2. Deuterium oxide enhanced photoemission 4.4-fold. Ascorbate inhibited chemiluminescence completely. In the absence of GSH or when GSH was replaced by the disulfide, no red chemiluminescence was observed. The glutathionyl radical GS. is most likely to be involved in both phases of light emission. Further, the superoxide radical plays a role, as substantiated by the inhibitory effect of superoxide dismutase. Both phases of photoemission were abolished by glutathione peroxidase; thus hydroperoxides are regarded as essential intermediates for the formation of excited species. Catalase abolished phase I and did not affect phase II. In contrast, glutathione S-transferase 1-2 (showing peroxidase activity towards organic hydroperoxides but not towards H2O2) inhibited phase II, whereas phase I was still present. Glutathione sulfonate and the disulfide GSSG were detected as oxidation products from GSH under conditions where phase II chemiluminescence was observed. HRP Compound III accumulated during the reaction. It is concluded that phase I is dependent on exogenously added or endogenously generated H2O2, whereas phase II does not require H2O2 but an organic peroxy species. A mechanism based on chain reactions involving oxygen addition to the thiyl radical is proposed. Sulfenyl peroxy species are suggested as transient intermediates in reactions finally leading to the generation of excited states such as singlet molecular oxygen.
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PMID:Excited species generation in horseradish peroxidase-mediated oxidation of glutathione. 301 81

The enzymes involved in antioxidative activity and the cellular content of the antioxidants glutathione and ascorbate in the cyanobacteria Nostoc muscorum 7119 and Synechococcus 6311 have been examined for their roles in hydroperoxide removal. High activities of ascorbate peroxidase and catalase were found in vegetative cells of both species and in the heterocysts of N. muscorum. The affinity of ascorbate peroxidase for H2O2 was 15- to 25-fold higher than that of catalase. Increased activity of ascorbate peroxidase was observed in N. muscorum when H2O2 production was enhanced by photorespiration. Catalase activity was decreased in dilute cultures whereas ascorbate peroxidase activity increased. Ascorbate peroxidase activity also increased when the CO2 concentration was reduced. Ascorbate peroxidase appears to be a key enzyme in a cascade of reactions regenerating antioxidants. Dehydroascorbate reductase was found to regenerate ascorbate, and glutathione reductase recycled glutathione. In vegetative cells glutathione was present in high amounts (2-4 mM) whereas the ascorbate content was almost 100-fold lower (20-100 microM). Glutathione peroxidase was not detected in either cyanobacterium. It is concluded from the high activity of ascorbate peroxidase activity and the levels of antioxidants found that this enzyme can effectively remove low concentrations of peroxides. Catalase may remove H2O2 produced under photooxidative conditions where the peroxide concentration is higher.
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PMID:Hydroperoxide metabolism in cyanobacteria. 308 78

Bactericidal effects of polyunsaturated fatty acids were investigated by using an in vitro killing assay. All gram-positive species tested were extremely susceptible to 10(-5) M arachidonic acid as were Neisseria, Branhamella, and Haemophilus spp. Pseudomonas aeruginosa and and members of the Enterobacteriaceae were resistant. The toxicity of polyunsaturated fatty acids for Staphylococcus aureus was dependent upon time, concentration, and fatty acid unsaturation. Arachidonic acid underwent peroxidation when incubated with S. aureus, but arachidonic acid peroxidation products had low bactericidal activity. Catalase protected S. aureus, whereas superoxide dismutase was ineffective. Scavengers of hydroxyl radicals or singlet oxygen or removal of halide ions had little effect on arachidonic acid-induced killing of bacteria, whereas transition metal chelators and some thiols were highly protective. S. aureus grown in iron-supplemented broth had increased iron content and arachidonic acid susceptibility. Ascorbate also potentiated arachidonic acid-induced killing of S. aureus. These observations indicate that bactericidal effects of polyunsaturated fatty acids are mediated by a peroxidative process involving H2O2 and bacterial iron.
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PMID:Bactericidal effects of polyunsaturated fatty acids. 308 65

Rat adrenal mitochondria have an active rotenone-insensitive outer mitochondrial membrane NADH-semidehydroascorbate (NADH-SDA) reductase which supports cholesterol side chain cleavage at a rate equal to that supported by malate. Side chain cleavage activity supported by both of these electron donor systems is equally inhibited by cycloheximide. Catalase or butylated hydroxyanisole are required for the NADH-SDA reductase-supported cholesterol side chain cleavage. This requirement can be removed by briefly subjecting the mitochondrial preparations to -20 degrees C. Ascorbic acid alone or with malate is either inhibitory or has no effect on side chain cleavage activity. These observations demonstrate that outer mitochondrial membrane NADH-SDA reductase in rat adrenal functions to provide cytoplasmic reducing equivalents to intramitochondrial cytochrome P-450scc and provides a new explanation for the function of ascorbic acid in corticosteroidogenesis.
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PMID:Cholesterol side chain cleavage in rat adrenal supported by outer mitochondrial membrane NADH-semidehydroascorbate reductase. 398 Apr 58

Ascorbic acid (vitamin C) was found to stimulate the chlorinating activity of human myeloperoxidase (donor:hydrogen peroxide oxidoreductase, EC 1.11.1.7) 3-fold in vitro and to shift the pH optimum of the reaction to higher pH values. These effects are due to the conversion by ascorbic acid of inactive compound II formed during turnover into native enzyme.
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PMID:Vitamin C stimulates the chlorinating activity of human myeloperoxidase. 631 33


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