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

The effect of complex formation between ferricytochrome c and cytochrome c peroxidase (Ferrocytochrome-c:hydrogen peroxide oxidoreductase, EC 1.11.1.5) on the reduction of cytochrome c by N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), reduced N-methylphenazonium methosulfate (PMSH), and ascorbate has been determined at low ionic strength (pH 7) and 25 degrees C. Complex formation with the peroxidase enhances the rate of ferricytochrome c reduction by the neutral reductants TMPD and PMSH. Under all experimental conditions investigated, complex formation with cytochrome c peroxidase inhibits the ascorbate reduction of ferricytochrome c. This inhibition is due to the unfavorable electrostatic interactions between the ascorbate dianion and the negatively charged cytochrome c-cytochrome c peroxidase complex. Corrections for the electrostatic term by extrapolating the data to infinite ionic strength suggest that ascorbate can reduce cytochrome c peroxidase-bound cytochrome c faster than free cytochrome c. Reduction of cytochrome c peroxidase Compound II by dicyanobis(1,10-phenanthroline)iron(II) (Fe(phen)2(CN)2) is essentially unaffected by complex formation between the enzyme and ferricytochrome c at low ionic strength (pH 6) and 25 degrees C. However, reduction of Compound II by the negatively changed tetracyano-(1,10-phenanthroline)iron(II) (Fe(phen)(CN)4) is enhanced in the presence of ferricytochrome c. This enhancement is due to the more favorable electrostatic interactions between the reductant and cytochrome c-cytochrome c peroxidase Compound II complex then for Compound II itself. These studies indicate that complex formation between cytochrome c and cytochrome c peroxidase does not sterically block the electron-transfer pathways from these small nonphysiological reductants to the hemes in these two proteins.
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PMID:The effect of complex formation upon the reduction rates of cytochrome c and cytochrome c peroxidase compound II. 303 33

Aerobic incubations of the Tritrichomonas foetus hydrogenosomal fraction containing pyruvate, CoA, and the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) gave spectra of two radical adducts. One was a carbon-centered radical adduct of DMPO. This radical was centered at C-3 of pyruvate as determined in experiments using [13C]pyruvate. The other radical detected was identified as the CoA radical adduct of DMPO by comparison with an adduct obtained by incubating CoA with DMPO, H2O2 and horseradish peroxidase. Deletion of CoA led to an increased stability of the carbon-centered radical adduct of DMPO, disappearance of the thiyl radical adduct of DMPO, and appearance of a hydroxyl radical adduct of DMPO. Superoxide dismutase suppressed the appearance of the DMPO-hydroxyl radical adduct but did not have any inhibitory effect on the appearance of the other adducts. Catalase had no significant effect on any of the adducts. Addition of pyruvate to these hydrogenosomal preparations stimulated oxygen consumption. Addition of CoA led to a further increase in the rate of O2 uptake but had no effect in the absence of pyruvate. The formation of two substrate free radicals as intermediates in the generation of acetyl-CoA represents a novel mechanism for this enzymatic reaction and indicates that the pyruvate:ferredoxin oxidoreductase from T. foetus differs significantly from the pyridine nucleotide-dependent pyruvate dehydrogenase complex of other eukaryotic cells in its catalytic mechanism.
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PMID:Free radical intermediates in the reaction of pyruvate:ferredoxin oxidoreductase in Tritrichomonas foetus hydrogenosomes. 304 Jul 44

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

The addition of luminol plus a catalyst such as peroxidase or a heme prosthetic group to a solution containing a small quantity of lipid hydroperoxides results in a flash of chemiluminescence, the intensity of which is a function of the hydroperoxide concentrations. Various protocols for lipid hydroperoxide assays have been described and we have studied conditions to increase their sensitivity and specificity. Plasma lipid hydroperoxide determinations require an extraction, since compounds present in plasma interfere with light emission. Moreover, the sensitivity of the assay is by the presence of hydrogen peroxide in the medium, which causes high background values. Catalase does not act on lipid hydroperoxides and can be used to eliminate hydrogen peroxide from the reaction medium. The determination requires a blank tube in which hydroperoxides are destroyed by incubating the sample with haematin plus ascorbate. The increase in the chemiluminescence of the assay tube caused by the presence of lipid hydroperoxides is then compared to the value obtained for an internal standard.
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PMID:Chemiluminescent assay of lipid hydroperoxides. 321 96

If H2O2 is one of the major mediators of the 'oxygen effect' in biological systems then catalase, which enzymically decomposes H2O2 should have a significant influence on radiation damage, particularly under oxygenated conditions. The post-irradiation (300 Gy gamma rays) effect of catalase was, therefore, assessed on barley seeds of about 4 per cent moisture content under oxygenated and oxygen-free conditions at varying temperatures. Catalase affords concentration-dependent radioprotection under oxygenated condition at both 25 degrees C and 4 degrees C. The level of protection at 4 degrees C is less than at 25 degrees C. This is obviously due to a decrease in catalase activity at low temperature. Under oxygen-free conditions, catalase enhances radiation damage at 4 degrees C while at 25 degrees C it has no effect. This has been substantiated by data on the frequency of chromosomal aberrations and on peroxidase activity. Sodium azide, a catalase inhibitor, was found to eliminate the radioprotective action of catalase. The study supports the view that the 'oxygen effect' is mediated largely through peroxides in irradiated biological systems. However, the observations made particularly at 4 degrees C under oxygen-free condition seem to involve physicochemical reactions.
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PMID:Post-irradiation modification of oxygen-dependent and independent damage by catalase in barley seeds. 349 10

The five mycobacteria Mycobacterium lepraemurium, M. leprae, M. bovis BCG, M. smegmatis, and M. intracellulare were studied. Catalase and peroxidase activities were demonstrated in polyacrylamide and crossed immunoelectrophoresis gels for M. lepraemurium, M. intracellulare, and BCG, but not for M. leprae. Peroxidase and catalase activities were associated with the same precipitate line in crossed immunoelectrophoresis for M. lepraemurium, M. intracellulare, and BCG, showing that in these mycobacteria the two enzyme activities resided in the same molecule. M. smegmatis peroxidase and catalase activities were closely associated on polyacrylamide gel electrophoresis, but on the crossed immunoelectrophoresis catalase and peroxidase activities were associated with two different precipitate lines. Catalases without peroxidase activity were demonstrated in crossed immunoelectrophoresis and polyacrylamide gel electrophoresis in M. intracellulare and M. smegmatis. The catalase without peroxidase activity in M. intracellulare was heat resistant and therefore classified as an m-catalase. In M. smegmatis the catalase without peroxidase activity was only partially heat resistant. All of the catalases with peroxidase activity were heat-sensitive t-catalases. Superoxide dismutase activity in the crossed immunoelectrophoresis was associated with the M. leprae antigen no. 4 and with cross-reacting antigens in the other mycobacteria studied. Several superoxide dismutases were demonstrated in Mycobacterium duvalii. They were antigenically different from the other superoxide dismutases in this study, as shown by lack of reactivity with a monospecific antibody to M. lepraemurium superoxide dismutase. Molecular weights were estimated for all the enzymes in this study by sodium dodecyl sulfate-polyacrylamide gels.
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PMID:Catalases, peroxidases, and superoxide dismutases in Mycobacterium leprae and other mycobacteria studied by crossed immunoelectrophoresis and polyacrylamide gel electrophoresis. 353 45

The organization of intracortical and callosal projecting cell bodies was examined in somatosensory representation areas I (SI) and II (SII) of the raccoon by use of horseradish peroxidase (HRP) or horseradish peroxidase-wheat germ agglutin (HRP-WHA). HRP and HRP-WHA were injected into commissurally and noncommissurally connected subdivisions of SI and SII. Injection sites in SII were identified electrophysiologically. Results were obtained from transverse sections in which the HRP was visualized with the aid of the substrates dihydrochlorobenzidine or tetramethyl benzidine in the presence of hydrogen peroxidase. The principal findings were the following: (1) there are reciprocal connections between SI and SII; (2) in SI the intracortically projecting cell bodies and terminals are located primarily in sulcal cortex; (3) intracortically projecting neurons in SI are located primarily in layers III whereas in SII they are located principally in layers III and V; (4) there are connections between disparate areas within SI; and (5) there are intracortical connections between callosum-connected and acallosal regions in SII. These results are discussed with regard to the results of mapping studies of the SI, the significance of intracortical connections to the formation of sulci in SI, and the possible roles of nonhomotopic connections in the intermanual transfer of learning.
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PMID:Organization of intracortical and commissural connections in somatosensory cortical areas I and II in the raccoon. 355 94

Catalase-peroxidase was isolated from aerobically grown Rhodopseudomonas capsulata. The enzyme resembles typical catalases in some of its physicochemical properties. It has an apparent molecular weight of 236,000 and is composed of four identical subunits. It shows a typical high spin ferric heme spectrum with absorption maxima at 403 and 635 nm and shoulders at 503 and 535 nm. Upon binding of cyanide, the enzyme is converted to the low spin state, as shown by the shift of the Soret maximum to 418 nm and the band at 532 nm. It has an isoelectric point at pH 4.5. The enzyme differs from typical catalases in also having a strong peroxidatic activity with dianisidine, pyrogallol, and diaminobenzidine as electron donors. Both the catalatic and the peroxidatic activities are similarly inactivated by treatment with 1 mM H2O2, heating to 50 degrees C, exposure to ethanol/chloroform, and photooxidative conditions. In contrast to typical catalases, but similarly to peroxidases, the enzyme is reduced by sodium dithionite. The pH optimum of the peroxidatic activity is 5-5.3 (in contrast to 6-6.5 of the catalatic activity). 50% of the apparent maximal activities are reached at 0.3 and 4.2 mM H2O2 for the peroxidatic and catalatic activities, respectively. Both enzymic activities are equally inhibited by cyanide, 50% inhibition being achieved with 2.2 X 10(-5) M KCN. Contrarily, the two activities differ in their response to hydroxylamine and azide. 50% inhibition of the catalatic activity is obtained with 1.5 X 10(-4) M azide or 2.15 X 10(-6) M hydroxylamine; 50% inhibition of the peroxidatic activity requires 7.3 X 10(-4) M azide or 7.8 X 10(-5) M hydroxylamine. The activation energies of the catalatic and the peroxidatic activities are 1.9 and 1.7 kcal/mol, respectively.
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PMID:Purification and characterization of a catalase-peroxidase from the photosynthetic bacterium Rhodopseudomonas capsulata. 357 Dec 90

Patients suffering from rheumatoid arthritis, spondylosis, coxarthrosis, ankylosing spondylitis, chronic active and chronic alcoholic hepatitis were studied. The plasma vitamin E content remained unchanged. The TBA-reactive plasma substances (malondialdehyde) content of plasma increased in all patients except those with ankylosing spondylitis. Catalase activity of plasma increased in patients of both sexes suffering from rheumatoid arthritis and spondylosis and coxarthrosis, but decreased in the two hepatitis groups. The glutathione-peroxidase activity of RBC (1:9 haemolysate) increased in female rheumatoid arthritis patients and decreased in those suffering from chronic alcoholic hepatitis. The results showed that chronic inflammatory processes affect the rate of lipid peroxidation and the activity of the biological antioxidant mechanism.
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PMID:Vitamin E content and lipid peroxidation of blood in some chronic inflammatory diseases. 359 51

Two dermatophyte strains, Trichophyton quinckeanum and Trichophyton rubrum, were highly susceptible to in vitro killing by components of the H2O2-peroxidase-halide system. Both strains were, however, resistant to relatively high concentrations of reagent H2O2 or H2O2 enzymatically generated by glucose and glucose oxidase, KI, or lactoperoxidase (LPO) alone. Resistance to hydrogen peroxidase killing was found to be in part due to the presence of endogenous catalase in the fungi; susceptibility was increased by pretreatment of the fungi with a catalase inhibitor. Kinetic studies using small quantities of reagent or enzymatically generated H2O2 and LPO-KI showed that the system was lethal for both fungal strains within 1 min. Furthermore, using the glucose-glucose oxidase-LPO-KI system, it was shown that catalase, superoxide dismutase and histidine scavengers of H2O2, superoxide anion and singlet oxygen, respectively, prevented the killing of fungus, whereas scavengers of hydroxyl radicals such as benzoate and mannitol had no effect. T. quinckeanum was found to contain large quantities of superoxide anion, as judged by the nitroblue-tetrazolium test. Consequently, the xanthine (or hypoxanthine) and xanthine oxidase system in which the main product is superoxide anion had no toxic effect on the fungus. The high sensitivity of dermatophytes to killing by the H2O2-peroxidase-halide system active in polymorphonuclear neutrophils and macrophages may account in part for fungal toxicity in vivo.
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PMID:Susceptibility of Trichophyton quinckeanum and Trichophyton rubrum to products of oxidative metabolism. 361 Feb 10


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