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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The extent of DNA damage and lipid peroxidation induced by myricetin, a polyphenolic flavonoid, were studied in isolated rat liver nuclei under aerobic conditions. Myricetin induced significant (P < 0.05) concentration-dependent nuclear DNA degradation concurrent with lipid peroxidation; these effects were enhanced by iron (III) or copper (II). Catalase, superoxide dismutase (SOD), mannitol and sodium azide did not inhibit myricetin-induced nuclear DNA damage in the presence of iron (III) or copper (II). However, all of these antioxidants stimulated myricetin-induced DNA damage in the presence of copper (II). Lipid peroxidation induced by myricetin was significantly inhibited only by SOD in the presence of copper (II), whereas it was enhanced by catalase and sodium azide in the presence of iron (III). These results demonstrate the pro-oxidant properties of polyphenolic flavonoids, which are generally considered to be antioxidants and anticarcinogens, and suggest a dual role for these flavonoids in mutagenesis and carcinogenesis.
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PMID:Interactions of flavonoids, trace metals, and oxygen: nuclear DNA damage and lipid peroxidation induced by myricetin. 833 Mar 5

Fanconi's anemia (FA) cells are highly susceptible to both reactive oxygen species and mitomycin C (MMC), a DNA cross-linking agent. In this study we have determined the amounts of 8-hydroxydeoxyguanosine (8OHdG), typical of oxidative DNA damage, in Epstein-Barr virus transformed lymphoblasts from FA patients and normal controls by the use of HPLC combined with electrochemical detection. FA cells (HSC72 and 99 cells being assigned to FA complementation group A) formed 2-3 times more 8OHdG than control cells after incubation with 20 mM H2O2 at 37 degrees C for 30 min. FA cells also formed more 8-hydroxyguanosine, typical of oxidative RNA damage, than control cells. FA cells showed decreased activity to decompose H2O2. Although the activity in FA cells was only 20-30% less than control cells, the remaining, undecomposed H2O2 concentration was almost twice as much in FA cells as in control cells, and the remaining H2O2 concentration correlated well with the amounts of 8OHdG formation. The H2O2 decomposing activity was almost completely inhibited by sodium azide (NaN3) or aminotriazole, both catalase inhibitors. With these inhibitors the amounts of 8OHdG formation were much higher than in those cells without inhibitors, and were almost the same in control cells as in FA cells. Catalase activity in FA cell lysates was 70-80% of controls. MMC also increased 8OHdG formation in FA cells only at ED100 but not at ED50. These results indicate that FA cells, at least FA complementation group A cells, have increased susceptibility to oxidative DNA damage, and that this increased susceptibility is possibly due to decreased catalase activity. These results also suggest that catalase plays an important role in protecting DNA from oxidative damage. However, this increased susceptibility to oxidative DNA damage is considered not to be the major cause of the increased susceptibility to MMC.
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PMID:Increased formation of 8-hydroxydeoxyguanosine, an oxidative DNA damage, in lymphoblasts from Fanconi's anemia patients due to possible catalase deficiency. 838 71

It was shown that superoxide dismutase (SOD) decreased the mutagenic action of sodium azide (NaN3) and N-methyl-N'-nitro-N-nitrosoguanidine in Salmonella typhimurium TA1535. Catalase and quenchers of hydroxyl radicals showed, unlike SOD no effect on the mutagenicity of NaN3. Cell extract from propionic acid bacteria also possessed the antimutagenic activity, only partially depending on the SOD activity.
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PMID:[Antimutagenic action of superoxide dismutase on sodium azide- and nitrosoguanidine-induced mutagenesis in Salmonella typhimurium TA 1535]. 839 62

The lung toxicity of a carbide-cobalt mixture is more important than that of each individual component; the mechanism of this interaction is not understood. The capacity of cobalt metal particles alone and mixed with different carbides to generate hydroxyl radicals was examined with the deoxyribose assay. In a chemical system, cobalt ions and cobalt metal particles (Co) were found to catalyse the degradation of deoxyribose in the presence of hydrogen peroxide. Carbides were able to directly oxidize deoxyribose, but their respective activities did not support such a mechanism to explain the carbide-cobalt interactive toxicity, since there was no direct relationship between deoxyribose degradation ability and cytotoxicity toward macrophages. Tungsten, niobium, titanium and chromium carbides (interactive carbides) were only weak oxidants and conversely molybdenum, vanadium and silicon carbides (non-interactive carbides) were the most potent ones. The ability of cobalt metal to produce hydroxyl radicals in the presence of hydrogen peroxide was not increased by tungsten carbide. The role of reactive radical formation in the toxicity of these particles was further assessed in a macrophage culture model. Catalase (4000 U/ml), superoxide dismutase (300 U/ml), sodium azide (1 mM), sodium benzoate, mannitol, taurine and methionine (all 20 mM) were all unable to protect against the cytotoxic effects of cobalt ions and cobalt metal alone or mixed with tungsten carbide. In conclusion, no evidence was found that production of reactive oxygen species contributes to the elective toxicity of carbide-cobalt mixtures.
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PMID:Evaluation of the role of reactive oxygen species in the interactive toxicity of carbide-cobalt mixtures on macrophages in culture. 839 91

We were recently able to measure intracellular levels of hydrogen peroxide within normal articular chondrocytes using the trapped indicator 2',7'-dichlorofluorescein diacetate. Further studies have shown that stimulated chondrocytes produce luminol-dependent chemiluminescence, suggesting that these cells produce hydrogen peroxide and singlet oxygen. In the present study, we have investigated the lucigenin-dependent chemiluminescence response in normal articular chondrocytes. Chondrocytes either in suspension or adhered to cover slips showed lucigenin-dependent chemiluminescence. There was a dose-dependent increase in chemiluminescence response when chondrocytes were incubated with soluble stimuli like phorbol-myristate-acetate, concanavalin A, and f-met-leu-phe. Catalase and the metabolic inhibitor, sodium azide, which inhibits the enzyme myeloperoxidase, had no inhibitory effect on lucigenin-dependent chemiluminescence production. Only the antioxidant, superoxide dismutase, prevented lucigenin-dependent chemiluminescence, indicating that this assay measures the production of superoxide anions by chondrocytes. We confirmed that chondrocytes release superoxide radicals using the biochemical assay of ferricytochrome c reduction. Since cartilage tissue is semi-transparent, we were able to measure chemiluminescence response in live cartilage tissue, showing that chondrocytes which are embedded within the matrix can also generate superoxide anion radicals. Reactive oxygen intermediates have been shown to play a significant role in the degradation of matrix in arthritis. Our previous and present studies suggest that oxygen radicals produced by chondrocytes may be an important mechanism by which chondrocytes induce cartilage matrix degradation.
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PMID:Lucigenin-dependent chemiluminescence in articular chondrocytes. 839 40

The influence of nitric oxide on human sperm hyperactivation and capacitation, as well as its mechanism of action and its possible origin from spermatozoa were studied. Percoll-washed spermatozoa from healthy volunteers were incubated in Ham's F-10 medium supplemented or not with the nitric oxide-releasing agents, diethylamine-NONOate or spermine-NONOate, in combination or not with superoxide dismutase or catalase (scavengers for the superoxide anion and for hydrogen peroxide, respectively), or with sodium nitrate, sodium nitrite, or preincubated NONOates. Sperm hyperactivation, capacitation, and nitric oxide synthase activity were determined. High concentrations (0.3 to 1 mM) of NONOates reduced sperm motility. However, a lower concentration (0.1 mM) of the two NONOates had no effect on the percentage of sperm motility or of hyperactivation but resulted in a significant increase in sperm capacitation (24% +/- 4%) when compared to that of control spermatozoa (Ham's F-10 alone, 12% +/- 2%). Nitric oxide released by the NONOates appeared responsible for this effect because sodium nitrate or nitrite or preincubated NONOates (to exhaust the formation of nitric oxide) had no influence on sperm capacitation. Catalase, but not superoxide dismutase, abolished the capacitating action of the NONOates. No nitric oxide synthase activity was detected in spermatozoa, whether they were in their basal state or already capacitated. Furthermore, the nitric oxide synthetase inhibitor L-NG nitroarginine methyl ester did not block sperm capacitation induced by fetal cord serum ultrafiltrate. It is therefore concluded that, although spermatozoa do not possess detectable nitric oxide synthase activity, low levels of nitric oxide induce human sperm capacitation, and this action likely involves hydrogen peroxide.
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PMID:Low levels of nitric oxide promote human sperm capacitation in vitro. 857 82

The effect of diesel exhaust particles (DEP) on the activity of catalase, an intracellular antioxidant, was investigated because H2O2 is a cytotoxic oxidant, and catalase released from alveolar cells is an important antioxidant in the epithelial lining fluid in the lung. DEP inhibited the activity of bovine liver catalase dose-dependently, to 25-30% of its original value. The inhibition of catalase by DEP was observed only in the presence of anions such as Cl-,Br-, or thiocyanate. Other anions, such as CH3COO- or SO4-, and cations such as K+, Na+, Mg2+, or Fe2+, did not affect the activity of catalase, even in the presence of DEP extract. Catalase from guinea pig alveolar cells and catalase from red blood cells were also inhibited by DEP extracts, as was catalase from bovine liver. These results suggest that DEP taken up in the lung and located on alveolar spaces might cause cell injury by inhibiting the activity of catalase in epithelial lining fluid, enhancing the toxicity of H2O2 generated from cells in addition to that of O2- generated by the chemical reaction of DEP with oxygen.
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PMID:Inhibition of catalase activity in vitro by diesel exhaust particles. 859 69

Cross-linking B cell antigen receptor (BCR) elicits early signal transduction events, including activation of protein tyrosine kinases, phosphorylation of receptor components, activation of phospholipase C-gamma (PLC-gamma), and increases in intracellular free Ca2+. In this article, we report that cross-linking the BCR led to a rapid translocation of cytosolic protein tyrosine phosphatase (PTP) 1C to the particulate fraction, where it became associated with a 140-150-kD tyrosyl-phosphorylated protein. Western blotting analysis identified this 140-150-kD protein to be CD22. The association of PTP-1C with CD22 was mediated by the NH2-terminal Src homology 2 (SH2) domain of PTP-1C. Complexes of either CD22/PTP-1C/Syk/PLC-gamma(1) could be isolated from B cells stimulated by BCR engagement or a mixture of hydrogen peroxidase and sodium orthovanadate, respectively. The binding of PLC-gamma(1) and Syk to tyrosyl-phosphorylated CD22 was mediated by the NH2-terminal SH2 domain of PLC-gamma(1) and the COOH-terminal SH2 domain of Syk, respectively. These observations suggest that tyrosyl-phosphorylated CD22 may downmodulate the activity of this complex by dephosphorylation of CD22, Syk, and/or PLC-gamma(1). Transient expression of CD22 and a null mutant of PTP-1C (PTP-1CM) in COS cells resulted in an increase in tyrosyl phosphorylation of CD22 and its interaction with PTP-1CM. By contrast, CD22 was not tyrosyl phosphorylated or associated with PTP-1CM in the presence of wild-type PTP-1C. These results suggest that tyrosyl-phosphorylated CD22 may be a substrate for PTP-1C regulates tyrosyl phosphorylation of CD22.
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PMID:CD22 associates with protein tyrosine phosphatase 1C, Syk, and phospholipase C-gamma(1) upon B cell activation. 862 66

We have studied the regulation of Na+/K(+)-ATPase function in alveolar type II cells submitted to oxidative stress. Alveolar type II cells were isolated from Sprague Dawley rats and suspended in Dulbecco's modified Eagle's medium. 500 muM xanthine plus 0.5 or 5 mU/ml xanthine oxidase (group 1 and 2, respectively) were added to the cell suspensions. Following various exposure times the reaction was stopped by adding allopurinol and cells were processed to assay H2O2 steady state concentrations, enzymatic activity of catalase and Na+/K(+)-ATPase function. Hydrogen peroxide production by the xanthine-xanthine oxidase system reached maximal values at 30 min of incubation in both groups. H2O2 steady state concentration increased 2- and 10-fold, respectively. Catalase activity was not changed after slight oxidative stress (group 1) but decreased in severe oxidative stress (group 2). Decreases in the Na+/K(+)-ATPase activity (10 and 60% for groups 1 and 2) were found during the first hour of exposure coinciding with the peak in H2O2 steady state concentration. This early inactivation was followed by progressive increases in the activity up to 70% over the control value in group 1, and to the control value in group 2. [3H]Ouabain binding studies showed that the increase in Na+/K(+)-ATPase activity after oxidative stress was due to an increase in the number of phosphorylated pump molecules in the plasma membrane of alveolar type II cells.
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PMID:Hydrogen peroxide increases Na+/K(+)-ATPase function in alveolar type II cells. 864 6

Helicobacter pylori exhibits a complex system of enzymes which serve a range of functions, such as colonization, damage of the host epithelium and provision of essential metabolic substrates. Colonization is favoured by urease and by the action on mucus and the mucosal barrier exerted by phospholipases and proteases, although this latter mechanism is controversial. Toxic effects are effected by urease, alcohol dehydrogenase (ADH), phospholipases and proteolytic enzymes. ADH produces acetaldehyde that is toxic to the mucosal cells, while phospholipases induce generation of products such as lysolecithin, which damage the gastric epithelium. Catalase and sodium dismutase of H. pylori are mainly involved in transforming toxic oxygen metabolites to harmless water; they protect the bacterium from the killing effect of neutrophils. Metabolic enzymes (for example, phosphatases, ATPases) are essential for the generation of energy, for synthesis and transport of cell products and for ion fluxes. In addition, they influence cell growth and the expression of virulence factors.
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PMID:Helicobacter pylori enzymes. 873 Feb 61


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