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

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

Catalase-like activity was determined in the cerebrospinal fluid of 16 patients with cerebral haemorrhage, 24 cases od encephalomalacia due to thrombosis, and 10 controls. It was demonstrated that catalase-like activity in the cerebrospinal fluid of patients with cerebral stroke is significantly raised in relation to the activity observed in controls. This rise is patricularly evident in the first 24 hours after the onset. The rise was statistically significant only in the group of encephalomalacia.
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PMID:[Catalase-like activity in cerebrospinal fluid in patients with cerebral stroke]. 120 96

Catalase and proteolytic activity of the culures and morphological variants of Bacillus mesentericus fuscus, Bac. mesentericus vulgatus were studied. The variants were obtained as a result of prolonged cultivation of the stock strains in the potato mash under the layer of vaseline oil. The level of catalase activity varies in different morphological variants of the same culture, changes with age and depends on the storage conditions. The catalase activity in the rough, smooth and papillar variants that were freshly isolated from the potato mash was 1.5=2.5 times lower than that in the variants long kept on the agar medium. The quantitative indexes of the proteolytic activity of different variants also varied.
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PMID:[Study of catalase and proteolytic activities of different variants of Bacillus mesentericus]. 120 11

Peroxisomes were present in trabecular carcinoma and adenocarcinoma induced by 3-methyl-4-(dimethylamino)azobenzene in the liver of rats. Peroxisomes in well-differentiated trabecular carcinoma (type I) resembled more or less those in hepatocytes in their electron microscopic features, but were considerably small in number. Poorly differentiated trabecular carcinoma (type II) and adenocarcinoma contained peroxisomes in far smaller number than in the well-differentiated trabecular carcinoma, or frequently showed no peroxisomes. Peroxisomes in poorly differentiated trabecular carcinoma and adenocarcinoma were small in size, contained scanty matrix in general, and almost lacked crystalloid nucleoids; however, they were easily identified by electron microscopic cytochemistry of catalase. Catalase activity of these tumors was significantly lower than in the liver tissues. These tumors did not respond to ethyl chlorophenxyisobutyrate either by proliferation of peroxisomes or by elevation of catalase activity. It is thus suggested that the cellular mechanisms for regulating the formation of peroxisomes and synthesis of the enzyme involved are impaired in the tumor cells.
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PMID:Peroxisomes in liver tumors of rats induced by 3'-methyl-4-(dimethylamino)azobenzene. 122 Sep 91

Catalase in hemolysates of normal, heterozygous hypocatalasemic and acatalasemic Japanese was immunotitrated with an anti-human blood catalase rabbit serum. Equivalence points were calculated from the regression lines between catalase activity added and catalase activity remaining in the supernatant. Catalase activities at the equivalence points of Japanese normal, hypocatalasemia and acatalasemia were similar. The results indicate that the specific activities of catalase in the normal and of the variant bloods are identical. Catalase in hemolysates of normal and variant mice was immunotitrated with an anti-mouse liver catalase rabbit serum. In contrast to Japanese acatalasemic subject, the equivalence points of catalase in heterozygous hypocatalasemic, homozygous hypocatalasemic, acatalasemic and normal hemolysates were different, and the ratios of specific activity in these variant mice to that in normal were 0.72, 0.46 and 0.21, respectively. The differences in catalase activities at equivalence points were also supported by the statistical analysis on parameters of regression lines of catalase activities remaining in the supernatant on catalase activities added in the immunotitration. These findings suggest that the molecular properties of residual catalase of Japanese acatalasemia and those of mouse acatalasemia are entirely different.
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PMID:Immunotitration of the catalase in the blood of Japanese subjects and mice suffering from acatalasemia and hypocatalasemia. 129 8

The oxidation of Fe2+ was investigated by electron spin resonance spin trapping techniques with N-t-butyl-alpha-phenylnitrone (PBN) and dimethyl sulfoxide. Under pure oxygen, the spin adduct PBN/.OCH3 was rapidly generated by the addition of Fe2+ (0.2-1.2 mM) into phosphate buffer containing ethylenediaminetetraacetate (EDTA), dimethyl sulfoxide, and PBN at pH 7.4, but it decayed. The decay process of PBN/.OCH3 consists of two components. The fast decay was dependent on Fe2+ concentration. Another was due to destruction of the spin adduct by superoxide anion (.O2-), because superoxide dismutase (SOD) markedly prevented the decay. Catalase decreased the yield of PBN/.OCH3. When EDTA was replaced by diethylenetriaminepentaacetic acid (DTPA), both the generation and decay process of PBN/.OCH3 were slow. SOD and catalase effects were similar to those in EDTA. Fe2+ produced PBN/.OCH3 even in the absence of chelators. We could estimate the kinetic parameters by computer simulation, comparing the Fe2+ oxidation in EDTA with that in DTPA. These results demonstrate that Fe2+ reacts with O2 to generate .O2- and then H2O2, which produces .CH3 by reaction with Fe2+ and dimethyl sulfoxide.(.)OCH3 results from the reaction between .CH3 and O2. The adduct PBN/.OCH3 decays by reaction with Fe2+ and .O2-.
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PMID:Spin trapping study on the kinetics of Fe2+ autoxidation: formation of spin adducts and their destruction by superoxide. 131 Nov 66

In an effort to understand the damaging actions of free radicals to neuronal electrophysiology, the superoxide generator, dihydroxyfumarate (DHF), was evaluated in slices of guinea pig hippocampus. Using field potential recording techniques, population spikes and population synaptic potentials were recorded in field CA1. Slices were exposed to 3 mM DHF either alone or in the presence of a protectant. DHF did not alter the ability of the afferent volley to generate a synaptic potential, but it did impair the ability of the synaptic potential to elicit a population spike. In addition, DHF induced lipid peroxidation as measured by the thiobarbituric acid assay. Superoxide dismutase (SOD) provided no protection. Instead, SOD treatment promoted DHF damage to synaptic potentials. Catalase alone mitigated the actions of DHF, but only in SOD plus catalase was the DHF-induced electrophysiological deficit and lipid peroxidation completely antagonized. The iron chelator, Desferal, did not protect but promoted synaptic damage. Desferal may be ineffective because of the nitroxide radical formed upon its reaction with DHF. The hydroxyl radical scavenger, dimethylsulfoxide, prevented lipid peroxidation and reduced the DHF-induced deficit but did not completely prevent the impairment of spike generation. These data suggest that DHF exerts its actions through generation of hydrogen peroxide which would further react with tissue iron to produce hydroxyl radicals.
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PMID:Electrophysiological consequences of exposure of hippocampal slices to dihydroxyfumarate, a generator of superoxide radicals. 131 16

Radiation produces a number of damaging radicals as well as peroxide. The chief cellular protection against these radicals, their secondary reactants and peroxide is the cellular glutathione (GSH), GSH peroxidase, GSH-S-transferase (GSHTase), and catalase enzymes. Inhibition of cellular catalase alone does not enhance the aerobic radiation response because cellular GSH peroxidase is equally effective in reducing peroxide. However, inhibition of GSHTase, and partial inhibition of peroxidase by L-buthionine sulfoximine (LBSO)-linked GSH depletion, results in an increased aerobic radiation response. The major pathway for peroxide reduction is the GSH peroxidase. The enzyme is accountable for 70% inactivation of low peroxide concentrations. Catalase accounts for the remaining inactivation. However, it is difficult to assess the relative contributions of GSHTase and peroxidase to the inactivation of radiation-produced hydroperoxides. Our data suggest that GSH depletion results in the inhibition of cellular GSHTase before it inhibits GSH peroxidase. Therefore, part of the increased aerobic radiation response maybe due to cellular inability to reduce hydroperoxides. Peroxide is not a substrate for GSHTase. However, total inhibition of peroxidase by L-BSO plus N-ethylmaleimide (NEM) treatment maximizes the aerobic radiation response. Total inhibition of GSH-S-transferase and peroxidase would block both peroxide and hydroperoxide reduction.
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PMID:The importance of peroxide and superoxide in the X-ray response. 131 73

Acetonitrile extracts of cigarette tar inhibit state 3 and state 4 respiration of intact mitochondria. Exposure of respiring submitochondrial particles to acetonitrile extracts of cigarette tar results in a dose-dependent inhibition of oxygen consumption and reduced nicotinamide adenine dinucleotide (NADH) oxidation. This inhibition was not due to a solvent effect since acetonitrile alone did not alter oxygen consumption or NADH oxidation. Intact mitochondria are less sensitive to extracts of tar than submitochondrial particles. The NADH-ubiquinone (Q) reductase complex is more sensitive to inhibition by tar extract than the succinate-Q reductase and cytochrome complexes. Nicotine or catechol did not inhibit respiration of intact mitochondria. Treatment of submitochondrial particles with cigarette tar results in the formation of hydroxyl radicals, detected by electron spin resonance (ESR) spin trapping. The ESR signal attributable to the hydroxyl radical spin adduct requires the presence of NADH and is completely abolished by catalase and to a lesser extent superoxide dismutase (SOD). Catalase and SOD did not protect the mitochondrial respiratory chain from inhibition by tar extract, indicating that the radicals detected by ESR spin trapping are not responsible for the inhibition of the electron transport. We propose that tar causes at least two effects: (1) Tar components interact with the electron transport chain and inhibit electron flow, and (2) tar components interact with the electron transport chain, ultimately to form hydroxyl radicals.
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PMID:The inhibitory effect of extracts of cigarette tar on electron transport of mitochondria and submitochondrial particles. 131 24

Active oxygen species cause gastric mucosal damage in vivo. However, it is not known if these species are directly cytotoxic toward gastric cells. Prostaglandins have important physiological roles in the gastric mucosa, including direct cell protection against damaging factors. So, to find if active oxygen species affect prostaglandin synthesis in gastric mucosal cells is important, but this also is not known. This study was done to investigate the effects of such species on damage to and prostaglandin synthesis in cultured mucus-producing cells from rat gastric mucosa. Active oxygen species were produced by the addition of xanthine and xanthine oxidase to the culture medium. Cytotoxicity was assayed by 51Cr release. Xanthine (1 mM) and xanthine oxidase (100 mU/ml) increased specific 51Cr release as the thiobarbituric acid reactants increased. This increase in 51Cr release was inhibited by catalase, a scavenger of hydrogen peroxide, or dimethyl sulfoxide, a scavenger of hydroxyl radicals, but not by superoxide dismutase, a scavenger of superoxide, nor deferoxamine, an inhibitor of hydroxyl radical generation. Catalase, dimethyl sulfoxide, and superoxide dismutase each had no effect on prostaglandin E2 synthesis when xanthine and xanthine oxidase were not added. In the presence of xanthine and xanthine oxidase, catalase and dimethyl sulfoxide stimulated the synthesis of prostaglandin E2 and superoxide dismutase inhibited it. Indomethacin, a prostaglandin synthetase inhibitor, did not affect the decrease in 51Cr release caused by catalase in the presence of xanthine and xanthine oxidase, but it abolished the decrease caused by dimethyl sulfoxide. These results suggest that hydrogen peroxide, but not superoxide nor hydroxyl radicals, is involved in damage to cultured rat gastric cells, and that superoxide stimulates prostaglandin E2 synthesis, but that hydrogen peroxide inhibits it. Protection of the cells by dimethyl sulfoxide may be related to stimulation of prostaglandin E2 synthesis in the cells, but not via scavenging hydroxyl radicals.
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PMID:Effects of active oxygen species on damage to and prostaglandin synthesis in cultured rat gastric cells. 132 36


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