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

Purified hyaluronic acid of ox vitreous humour was isolated treating the acetone precipitate of a vitreous humour homogenate with 1 M NaCl solution and thereafter with cetylpyridiniumchloride. Both disc-electrophoresis and hydroxyproline content proved the absence of collagen in the purified hyaluronic acid. FeSO4, ascorbate, and cysteine changed the hyaluronic acid molecule and lowered the viscosity of the hyaluronic acid solution, EDTA alone did not affect the viscosity but enhanced the effectiveness of iron ions or ascorbate on the viscosity of the solution. Catalase prevented the reduction of the viscosity by the above mentioned substances. Therefore, it is suggested that H2O2 and free radicals are generated during the reaction. The free radicals produced are responsible for the change of the hyaluronic acid molecule.
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PMID:[The change of hyaluronic acid of the vitreous humour by oxidation-reduction-systems (author's transl)]. 82 40

In photosynthetically competent chloroplasts from spinach the quantum requirements for oxygen evolution during CO2 reduction were higher, by a factor often close to 1.5, than for oxygen evolution during reduction of phosphoglycerate. Mass spectrometer experiments performed under rate-limiting light indicated that an oxygen-reducing photoreaction was responsible for the consumption of extra quanta during carbon dioxide assimilation. Uptake of 18O2 during reduction of CO2 was considerably higher than could be accounted for by oxygen consumption during glycolate formation and by the Mehler reaction of broken chloroplasts which were present in the preparations of intact chloroplasts. The oxygen reducing reaction occurring during CO2 assimilation resulted in the formation of H2O2. This was indicated by a large stimulation of CO2 reduction by catalase, but not of phosphoglycerate reduction. Catalase could be replaced as a stimulant of photosynthesis by dithiothreitol or ascorbate, compounds known to react with superoxide radicals. There was no effect of dithiothreitol and ascorbate on phosphoglycerate reduction. A main effect of superoxide radicals and/or H2O2 was shown to be at the level of phosphoglycerate formation. Evidence for electron transport of oxygen was also obtained from 14CO2 experiments. The oxidation of dihydroxyacetonephosphate during a dark period or after addition of carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone in the light was studied. The results indicated a link between the chloroplast pyridine nucleotide system and oxygen. Oxygen reduction during photosynthesis under conditions where light is rate limiting is seen as important in supplying the ATP which is needed for CO2 reduction but is not provided during electron transport to NADP. A mechanism is discussed which would permit proper distribution of electrons between CO2 and oxygen during photosynthesis.
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PMID:Reduction of oxygen by the electron transport chain of chloroplasts during assimilation of carbon dioxide. 119 61

Both nitric oxide (NO) and superoxide are generated by macrophages, neutrophils and endothelial cells. It has been postulated that the generation of these two radicals under physiological conditions can lead to the formation of peroxynitrite and (as a result of the homolytic lysis of this molecule) the production of hydroxyl radicals. We have used 3-morpholinosydnonimine N-ethylcarbamide (SIN-1), a sydnonimine capable of generating both NO and superoxide simultaneously, to test this hypothesis. SIN-1 (1 mM) generated superoxide and NO at rates of 7.02 microM/min and 3.68 microM/min respectively in phosphate-buffered saline, pH 7.2, at 37 degrees C. Incubation of SIN-1 with both deoxyribose and sodium benzoate resulted in the formation of malondialdehyde (MDA). In addition, the incubation of SIN-1 with sodium benzoate resulted in the production of compounds with fluorescence emission spectra characteristic of hydroxylated products. Both the production of MDA and the generation of fluorescent compounds were inhibited by the hydroxyl radical scavenger mannitol. In all the above respects, SIN-1 mimicked the production of hydroxyl radicals from the ascorbate-driven Fenton reaction. Catalase had no effect on the SIN-1-dependent generation of MDA, and superoxide dismutase was partially inhibitory. SIN-1 produces an oxidant with the properties of the hydroxyl radical by a mechanism clearly different to that of the Fenton reaction. We conclude that the simultaneous production of NO and superoxide from SIN-1 results in the formation of hydroxyl radicals.
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PMID:Production of hydroxyl radicals from the simultaneous generation of superoxide and nitric oxide. 131 May 95

The site-specific lysozyme damage by iron and by iron-catalysed oxygen radicals was investigated. A solution of purified lysozyme was inactivated by Fe(II) at pH 7.4 in phosphate buffer, as tested on cleavage of Micrococcus lysodeikticus cells; this inactivation was time- and iron concentration-dependent and was associated with a loss of tryptophan fluorescence. In addition, it was reversible at pH 4, as demonstrated by lysozyme reactivation and by the intensity of the 14.4-kD-band on SDS-PAGE. Desferal (1 mM) and Detapac (1 mM) added before iron, prevented lysozyme inactivation, while catalase (100 micrograms/ml), superoxide dismutase (100 micrograms/ml) and bovine serum albumin (100 micrograms/ml) gave about 30 to 40% protection by competing with lysozyme for iron binding. The denaturing effect of iron on lysozyme was studied in the presence of H2O2 (1 mM) and ascorbate (1 mM); under these conditions the enzyme underwent partly irreversible inactivation and degradation different to that produced by gamma radiolysis-generated .OH. Catalase almost fully protected lysozyme; in contrast, mannitol (10 mM), benzoate (10 mM), and formate (10 mM) provided no protection because of their inability to access the site at which damaging species are generated. In this system, radical species were formed in a site-specific manner, and they reacted essentially with lysozyme at the site of their formation, causing inactivation and degradation differently than the hydroxyl radical.
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PMID:Mechanism of lysozyme inactivation and degradation by iron. 133 14

Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl radical (HO.) generating systems of xanthine oxidase (XO) + EDTA-Fe3+ and ascorbate + EDTA-Fe3+. Formation of bityrosine and loss of tryptophan were observed in the ascorbate + EDTA-Fe3+ system and carbonyl formation was induced by both systems. Mannitol and ethanol very strongly inhibited the carbonyl and/or bityrosine formation, indicating that the oxidative damage to BSA was due to HO(.). The sulfhydryl (SH) groups of BSA were very sensitive to the XO + EDTA-Fe3+ but not to the ascorbate + EDTA-Fe3+ system. Catalase but not hydroxyl radical scavengers or superoxide dismutase strongly inhibited the loss of SH groups, indicating that H2O2 is involved in their oxidation. Fragmentation of BSA was observed during exposure to the XO + EDTA-Fe3+ and ascorbate + EDTA-Fe3+ systems and the products presented a broad band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Little formation of amine groups was observed in these systems, indicating that little peptide bond cleavage occurred. BSA exposed to the ascorbate + EDTA-Fe3+ system was more readily degraded by trypsin than that exposed to the XO + EDTA-Fe3+ system. Elastase degraded BSA exposed to the ascorbate + EDTA-Fe3+ system but not to the XO + EDTA-Fe3+ system.
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PMID:Oxidative damage to bovine serum albumin induced by hydroxyl radical generating systems of xanthine oxidase + EDTA-Fe3+ and ascorbate + EDTA-Fe3+. 133 12

1. The hydroxyl radical-mediated conversion of morphine to morphinone (MO) was examined as an alternative to the enzymic reaction. 2. Hydroxyl radicals were generated by autoxidation of ascorbate in the presence of iron and EDTA. This system oxidized morphine to MO which was identified by h.p.l.c. and t.l.c. The reaction was dependent on the concentration of added Fe2+ and required the addition of ascorbate when Fe3+ was used. 3. Catalase inhibited production of MO whereas superoxide dismutase (SOD) had no effect. Addition of a large amount of H2O2 to the system resulted in a significant decrease in production of MO. No MO production was initiated by H2O2 itself. The oxidation of morphine was inhibited by typical hydroxyl radical-scavenging agents. These results indicate that morphine undergoes oxidation to MO by hydroxyl radical.
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PMID:Hydroxyl radical-mediated conversion of morphine to morphinone. 138 46

In this report the mediatory role of copper in cardiac injury produced by reactive oxygen intermediates was examined. Isolated rat hearts were perfused with Krebs-Henseleit buffer containing 0.25 mM ascorbate plus varying concentrations of copper-bis-histidial for up to 60 min. Using salicylate as a probe, OH generation by this system was demonstrated. Copper or ascorbate alone had minimal effect on cardiac function as determined by heart rate, coronary flow, left ventricular systolic pressure development, end diastolic pressure and +/- dP/dtmax. Copper, from 0.5 microM to 20 microM, and ascorbate, 0.25 mM, resulted in concentration-dependent decreases in all of the experimental variables. Treatment with 5 or 20 microM copper resulted in complete loss of cardiac function within 40 and 30 min, respectively. By 30 min, 5 microM copper had resulted in increased end diastolic pressure to greater than 40 mmHg. By 60 min, perfusion with 1 microM copper resulted in almost 100% loss of function and end diastolic pressure greater than 25 mmHg. Copper, 0.5 microM, also decreased cardiac function, but to a lesser degree. Catalase, 100 units/ml, was effective in preventing the copper-ascorbate induced cardiac damage while superoxide dismutase, 25 units/ml, was ineffective. Observations by light and electron microscopy demonstrated patchy regions with vacuolization corresponding to swollen mitochondria. These results clearly demonstrate that copper-catalyzed redox reactions can induce cardiac injury via a mechanism which appears to be related to the production of OH.
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PMID:Mediatory role of copper in reactive oxygen intermediate-induced cardiac injury. 147 26

The oxidative demethylenation reactions of (methylendioxy)phenyl compounds (MDPs), (methylenedioxy)benzene (MDB), (methylenedioxy)amphetamine (MDA), and (methylenedioxy)methamphetamine (MDMA), were evaluated by using two hydroxyl radical generating systems, the autoxidation of ascorbate in the presence of iron-EDTA and the iron-catalyzed Haber-Weiss reaction conducted by xanthine/xanthine oxidase with iron-EDTA. Reaction products generated when MDB, MDA, and MDMA were incubated with the ascorbate or xanthine oxidase system were catechol, dihydroxyamphetamine (DHA), and dihydroxymethamphetamine (DHMA), respectively. The reaction required the presence of either ascorbic acid or xanthine oxidase. Levels of each catechol increased in proportion to ferric ion concentration and were suppressed by desferrioxamine B methanesulfonate (desferal). Catalase (CAT) inhibited the oxidation by the ascorbate system whereas superoxide dismutase (SOD) had little effect. The addition of hydrogen peroxide to the reaction mixture stimulated the oxidation, but the reaction was not initiated by hydrogen peroxide alone, suggesting that hydrogen peroxide acts as a precursor of hydroxyl radical. SOD and CAT suppressed the demethylenation reactions in the xanthine oxidase system. Hydroxyl radical scavenging agents such as ethanol, benzoate, DMSO, and thiourea effectively inhibited the oxidation by both systems. Urea, which has little effect on hydroxyl radical, was without any effect. These results indicated that hydroxyl radical can effect the cleavage of methylenedioxy group on MDPs.
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PMID:Hydroxyl radical mediated demethylenation of (methylenedioxy)phenyl compounds. 168 Apr 77

Desferrioxamine (DFO) nearly doubles alkaline phosphatase oxidative inactivation by the ascorbate system. The effect is dependent on ascorbate and desferrioxamine concentrations, exhibiting in both cases a saturation mechanism. Conversion of desferrioxamine to ferrioxamine abolishes the prooxidant action. Desferrioxamine also increases ascorbate-dependent oxygen consumption and nitroblue tetrazolium reduction. Superoxide dismutase, which blocks the desferrioxamine enhancing effect on enzyme inactivation, markedly slows down nitroblue tetrazolium reduction as well as oxygen consumption by ascorbate plus desferrioxamine, while it fails to protect against the ascorbate system alone. Therefore, in the presence of desferrioxamine, the metal-catalyzed ascorbate autooxidation becomes superoxide-dependent and thus inhibitable by superoxide dismutase. Catalase, peroxidase, and ascorbate oxidase protect alkaline phosphatase from inactivation by both ascorbate and ascorbate-desferrioxamine systems. Hemin shields the enzyme from ascorbate plus DFO attack but not from ascorbate alone. In air-saturated solution, desferrioxamine seems to mediate one electron transfer from ascorbate to oxygen, generating superoxide anions, which can either trigger a Fenton reaction or produce desferal nitroxide radicals. In the absence of oxygen, ascorbate alone is ineffective, but the ascorbate plus desferrioxamine system still inactivates the enzyme; catalase, peroxidase, and ascorbate oxidase, but not superoxide dismutase, afford protection.
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PMID:Prooxidant action of desferrioxamine: enhancement of alkaline phosphatase inactivation by interaction with ascorbate system. 215 77


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