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

A chemically defined liquid medium has been developed for the study of the physiology and antigen production of the Legionnaires disease bacterium. The medium contains basal salts, vitamins, alpha-ketoglutaric acid, pyruvate, 0.05% l-cysteine, 0.05% glutathione, and a mixture of 20 additional amino acids, each of 0.01% final concentration, except serine, which was at 0.1%. The medium in shake culture at 37 degrees C with increased CO2 at pH 6.5, supports the maximum rate of growth, the highest cell yields, and the maximum cell surface antigen as distinguished by specific fluorescein isothiocyanate-conjugated antibody. Studies during the development of this medium showed that CO2, pyruvate, and alpha-ketoglutarate strongly stimulated growth; that cysteine and methionine were required for growth; and that serine, threonine, histidine, tyrosine, and tryptophane were energy sources. Glutathione substituted for cysteine, but cystine did not. The organisms did not use glucose and polysaccharides, as judged by cell yields when these carbohydrates were present or absent. The chelators malate, citrate, and ethylenediaminetetraacetic acid totally inhibited growth. Beta-mercaptoethanol, thioglycolate, dithiothreitol, and Tween 80 (0.05%) inhibited growth strongly or completely. Catalase activity was extremely weak or absent. Morphology varied, depending upon conditions and phases of growth. In general, filamentous forms became chains of cigar-shaped bacilli fragmenting to pairs and becoming coccoidal in the late stationary pha-e of growth. The organism grew at 25, 30, and 37 degrees C. Although they varied in their growth characteristics, 10 isolates were passed for five transfers in the chemically defined broth, giving maximum rates of growth, cell yields, and antigen production.
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PMID:Development of a chemically defined liquid medium for growth of Legionella pneumophila. 3 86

1. Haemogloblin and myoglobin enhance rat liver microsomal p-hydroxylation of aniline and acetanilide. Microsomal N-demethylation of ethylmorphine and aminopyrine is not increased by haemoproteins. 2. The enhancement of microsomal p-hydroxylation is maximal at high substrate concentration and high haeme compound concentration. 3. Detergent-purified NADPH-cytochrome c reductase, free flavins and manganese ions considerably increase the haemoglobin-mediated, tissue-free hydroxylation of aniline. Microsomal aniline hydroxylation is not enhanced by haeme, ferric ion or albumin. 4 Catalase and cyanide ions are powerful inhibitors of haemoglobin-mediated aniline hydroxylation both in the presence and absence of tissue. Carbon monoxide inhibits the hydroxylase activity of the tissue-free system to a smaller extent than that of a system containing microsomes plus haemoglobin whereas p-chloromercuribenzoate inhibits only the flavoprotein-dependent hydroxylation of aniline mediated by haemoglobin. 5. Several possibilities of interactions between substrate, microsomes and haeme compounds are proposed.
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PMID:Enhancement of microsomal aniline and acetanilide hydroxylation by haemoglobin. 82 88

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

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

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

In the presence of intact Ehrlich ascite carcinoma cells and the supernatant obtained by preincubation and subsequent precipitation of cells, egg phosphatidylcholine is oxidized in liposomes to form malonic dialdehyde (MDA). Catalase and carbon dioxide markedly reduce, whereas sodium azide increases MDA accumulation during liposome incubation with the cells. EDTA, diethylthiocarbonate and alpha-tocopherol effectively inhibit, whereas ascorbate and cysteine strongly activate MDA synthesis in both cases. Superoxide dismutase has no appreciable effect on these processes. It is concluded that metal-containing catalysts and the H2O2 released by intact cells into the incubation medium induce lipid peroxidation in liposomes.
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PMID:[Mechanism of formation of malonic dialdehyde during liposome interaction with cells]. 320 6

A method was developed to grow Legionella pneumophila in continuous culture. A chemostat was used to simulate nutrient-limited, submaximal growth in the natural environmental and to provide a precisely controlled growth regimen. Cultures grew under forced aeration under conditions yielding up to 38% saturation of dissolved oxygen; supplemental CO2 (5%) at the same gas flow rates as ambient air had no effect on culture growth. Pleomorphism was observed during growth under all conditions. Pigment was produced only at D less than 0.03 h-1. Catalase was produced at higher growth rates but not at higher temperatures. The pathogenicity was unaffected by altering either the growth rate or the growth temperature.
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PMID:Growth of Legionella pneumophila in continuous culture. 401 91

1. Oxygen was taken up rapidly when pyridoxal or pyridoxal phosphate was added to mixtures of pea-seedling extracts and Mn(2+) ions. 2. The increases in total oxygen uptake were proportional to the pyridoxal or pyridoxal phosphate added and were accompanied by the disappearance of these compounds. 3. In addition to Mn(2+) ions, the reactions depended on two factors in the extracts, a thermolabile one in the non-diffusible material and a thermostable one in the diffusate; these factors could be replaced in the reactions by horse-radish peroxidase (donor-hydrogen peroxide oxidoreductase, EC 1.11.1.7) and amino acids respectively. 4. When pyridoxal phosphate was added to mixtures of amino acids and Mn(2+) ions oxygen uptake was rapid after a lag period of 30-90min.; the lag period was shortened to a few minutes by peroxidase, particularly in the presence of traces of p-cresol, or by light. 5. When pyridoxal replaced pyridoxal phosphate relatively high concentrations were required and peroxidase had only a small activating effect. 6. Pyridoxal or pyridoxal phosphate disappeared during the reactions and carbon dioxide and ammonia were formed. 7. With phenylalanine as the amino acid present, benzaldehyde was identified as a reaction product. 8. It is suggested that the reactions are oxidations of the Schiff bases formed between pyridoxal or pyridoxal phosphate and amino acids, mediated by a manganese oxidation-reduction cycle, and resulting in oxidative decarboxylation and deamination of the amino acids.
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PMID:The oxidation of Schiff bases of pyridoxal and pyridoxal phosphate with amino acids by manganous ions and peroxidase. 594 50

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a potent tobacco-specific carcinogen, has been demonstrated to induce lung tumors in animals and is suspected to be a human carcinogen. Cytochromes P450 are the major enzymes responsible for the activation of NNK in microsomes from the lung and liver of rat and mouse, as well as human liver. The present study investigated the enzymes responsible for the metabolic activation of NNK in human lung microsomes. In the presence of a NADPH-generating system, the formation of keto aldehyde and keto alcohol (alpha-hydroxylation products, measured together), keto acid, hydroxy acid, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol was observed in human lung microsomes. Carbon monoxide (90%) decreased the rate of NNK oxidation by 5-49%, depending on the human lung microsomal samples analyzed. Coumarin decreased the oxidation of NNK by 9-34%, and an antibody against human P450 2A6 decreased the metabolism of NNK by 8-37%, suggesting the involvement of P450 2A6 in NNK oxidation. alpha-Napthoflavone inhibited NNK oxidation by 6-26%, possibly due to the inhibition of P450 1A1. P450 1A1-expressed microsomes catalyzed the formation of keto aldehyde and keto alcohol, exhibiting Km values of 1400 microM and 371 microM, respectively. In the absence of NADPH, NNK metabolism resulted in the formation of keto acid, keto aldehyde, and keto alcohol, and the activities in different lung samples were decreased by indomethacin (100 microM; cyclooxygenase inhibitor) or nordihydroguaiaretic acid (100 microM; lipoxygenase inhibitor) by 0-27% or 30-66%, respectively. The addition of arachidonic acid (10-100 microM) increased the rate of the formation of keto aldehyde and keto alcohol approximately 2-fold but inhibited the formation of keto acid. Soybean lipoxygenase increased the rate of formation of keto aldehyde and keto alcohol in a concentration-dependent manner. The increased rate in NNK oxidation by arachidonic acid or lipoxygenase was inhibited completely by nordihydroguaiaretic acid. Catalase, thiourea, and conjugated linoleic acid decreased the rate of NNK oxidation by 47, 20, and 45%, respectively. tert-Butyl-hydroperoxide, cumene hydroperoxide, and hydrogen peroxide increased the rate of formation of keto aldehyde and keto alcohol by 210, 40, and 50%, respectively. The results suggest that P450 enzymes are only partially responsible for the activation of NNK in human lung microsomes, and P450 2A6 or a P450 2A6-related enzyme seems to be involved in the activation. Furthermore, lipoxygenase and lipid hydroxperoxides may play important roles in the oxidation of NNK in human lung microsomes.
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PMID:Activation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in human lung microsomes by cytochromes P450, lipoxygenase, and hydroperoxides. 758 36

The effects of hypoxia (95% N2/5% CO2) followed by hyperoxia (95% O2/5% CO2) were determined in isolated lungs of premature (gestational age 128 to 135 d) and full-term (postnatal age 0 to 5 d) lambs perfused with autologous blood (100 mL.min-1.kg body weight-1). In full-term lungs, hypoxia-hyperoxia compared with hypoxia alone decreased pulmonary artery pressure and increased weight gain and extravascular lung water. In premature lungs, the increase in weight gain was greater and was associated with hemorrhage and increased pulmonary arterial and peak airway pressures. Papaverine eliminated reoxygenation-induced differences in pulmonary artery pressure, peak airway pressure, and weight gain in both age groups. Osmotic reflection coefficients for total protein and albumin, measured by a modification of the filtered volume technique, averaged 0.591 +/- 0.054 (SEM) and 0.465 +/- 0.054 (SEM), respectively, and were not altered by reoxygenation or age. Catalase activity in lung tissue and erythrocytes was lower in premature lambs, but there were no age-related differences in superoxide dismutase or glutathione peroxidase activities. These results demonstrate that hypoxia-hyperoxia in isolated lamb lungs increased lung weight due to edema formation in full-term lamb lungs and hemorrhage in premature lamb lungs and that this increase was greater in premature lamb lungs. We speculate that the weight gain caused by reoxygenation was due to a vasodilation-induced increase in surface area in full-term lamb lungs and a vasoconstriction-induced increase in vascular pressure in premature lamb lungs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Developmental differences in catalase activity and hypoxic-hyperoxic effects on fluid balance in isolated lamb lungs. 851 Oct 27


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