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

1) Catalase from green leaves of Lens culinaris (lentils) was investigated with respect to isoenzyme patterns. In contrast to other plants, which have been reported to contain multiple forms of catalase, only one form of this enzyme was revealed when crude extracts were subjected to starch gel electrophoresis or to polyacrylamide disc-gel electrophoresis. Furthermore, catalases from leaves, stems and cotyledons were electrophoretically identical. 2) The leaf enzyme has been purified by conventional methods to apparent homogeneity. It has a molecular weight of 225 000 (ultracentrifuge) and is composed of four identical subunits of molecular weight 54 000 (sodium dodecylsulphate gel electrophoresis). The ratio A280/A405 of the pure enzyme was found to be 1.5. The isoelectric point is at pH 5.5. The enzyme, very labile at pH-values below 7.0, is stable in Tris chloride and potassium phosphate buffers between pH 7.5 and 9.5. It is slowly inactivated by 1mM dithiothreitol and is rapidly inactivated by 1mM mercaptoethanol. 3) The catalase was shown to be the major protein component of the peroxisomal matrix. It could not be detected at the membranes of the leaf peroxisomes.
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PMID:Plant microbody proteins, I. Purification and characterization of catalase from leaves of lens culinaris. 0 64

The distribution of catalase and D-amino acid oxidase, marker enzymes for peroxisomes, was determined cytochemically in the kidney tubules of an euryhaline teleost, the three-spined stickleback. Catalase activity was localized with the diaminobenzidine technique. The presence of D-amino acid oxidase was determined using H2O2 generated by the enzyme, D-alanine as a substrate, and cerous ions for the formation of an electron-dense precipitate. Both enzymes appeared to be located in microbodies. The combined presence of these enzymes characterizes the microbodies as peroxisomes. Biochemically and cytochemically, no urate oxidase or glycolate-oxidizing L-alpha-hydroxy acid oxidase could be demonstrated. Stereological analysis of the epithelia lining the renal tubules showed that the fractional volume of the microbodies is 5 to 10 times higher in the cells of the second proximal tubules than in the other nephronic segments or the ureter. The fractional volume of the microbodies was similar in kidneys of freshwater and seawater fishes.
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PMID:The cytochemical demonstration of catalase and D-amino acid oxidase in the microbodies of teleost kidney cells. 1 91

Methoxypolyethylene glycols of 1900 daltons (PEG-1900) or 5000 daltons (PEG-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. Rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups (PEG-1900-catalase). The intravenous antiserum did not yield detectable antibodies against PEG-1900-catalase or native catalase, as determined by Ouchterlony and complement fixation methods, whereas the intramuscular antiserum contained antibodies to both PEG-1900-catalase and catalase. PEG-1900 did not react with either antiserum. Catalase was prepared in which PEG-5000 was attached to 40% of the amino groups (PEG-5000-catalase). This catalase preparation did not react with either antiserum. PEG-1900-catalase retained 93% of its enzymatic activity; PEG-5000-catalase retained 95%. PEG-5000-catalase resisted digestion by trypsin, chymotrypsin, and a protease from Streptomyces griseus. PEG-1900-catalase and PEG-5000-catalase exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections. No evidence was seen of an immune response to injections of the modified enzymes. Mice injected repetitively with PEG-5000-catalase remained immune competent for unmodieied catalase, and no evidence of tissue or organ damage was seen.
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PMID:Effect of covalent attachment of polyethylene glycol on immunogenicity and circulating life of bovine liver catalase. 1 7

Partially purified soluble rat liver guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] was activated by superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1). This activation was prevented with KCN or glutathione, inhibitors of superoxide dismutase. Guanylate cyclase preparations formed superoxide ion. Activation by superoxide dismutase was further enhanced by the addition of nitrate reductase. Although guanylate cyclase activity was much greater with Mn2+ than with Mg2+ as sole cation cofactor, activation with superoxide dismutase was not observed when Mn2+ was included in incubations. Catalase also decreased the activation induced with superoxide dismutase. Thus, activation required the formation of both superoxide ion and H2O2 in incubations. Activation of guanylate cyclase could not be achieved by the addition of H2O2 alone. Scavengers of hydroxyl radicals prevented the activation. It is proposed that superoxide ion and hydrogen peroxide can lead to the formation of hydroxyl radicals that activate guanylate cyclase. This mechanism of activation can explain numerous observations of altered guanylate cyclase activity and cyclic GMP accumulation in tissues with oxidizing and reducing agents. This mechanism will also permit physiological regulation of guanylate cyclase and cyclic GMP formation when there is altered redox or free radical formation in tissues in response to hormones, other agents, and processes.
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PMID:Activation of guanylate cyclase by superoxide dismutase and hydroxyl radical: a physiological regulator of guanosine 3',5'-monophosphate formation. 2 77

Glutathione peroxidase (glutathione:hydrogen peroxide oxidoreductase, EC 1.11.1.9) was purified from rat liver mitochondria. The enzyme was shown to be pure by polyacrylamide-gel electrophoresis and to contain multiple forms that differed in charge. Selenium was specifically associated with the enzyme. The enzyme was inhibited by iodoacetic acid and iodoacetamide in an unusual pattern of reduction by sulfhydryl compounds and pH dependency. The mitochondrial and cytoplasmic forms of the enzyme were compared, and an explanation of the inhibition patterns is offered.
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PMID:Purification and properties of rat liver mitochondrial glutathione peroxidase. 2 81

The effect of ionic strength and pH on the release of some enzymes of the matrix of peroxisomes in rat's liver was studied. Catalase, L ALpha-hydroxy acid oxidase, isocitrate dehydrogenase, glycerophosphate dehydrogenase and lactate dehydrogenase were easily released from the particles during their lysis and treatment with 0.16 M KCl, whereas urate oxidase, NADH cytochrome c reductase and D-amino acid oxidase were not solubilized. After the solubilization of peroxisomal membrane by 0.2% Triton X-100, the remaining core contained about 50% amino acid oxidase activity, and had 1.28--1.30 g/cm3 density. These results suggest that D-amino acid oxidase associates with urate oxidase in the peroxisomal core.
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PMID:[Enzymologic study of the structural organization of the matrix or rat liver peroxisomes]. 2 68

The paper confirms the existence of a peroxide mechanism involved in oxidation of iron and manganeses by the most typical iron bacteria growing at neutral acidity of the medium. Oxidation of bivalent iron and manganese is accomplished by the simultaneous action of catalase and hydrogen peroxide produced in the respiratory chain in the course of oxidation of organic substances. Catalase performs the peroxidase function in these processes. The possibility of these biological reactions to occur and the necessary conditions have been studied in vitro. Possible variants of iron and manganese oxidation by iron bacteria are discussed, including the conditions for "symbiotic" oxidation of manganese by mixed cultures of microorganisms.
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PMID:[Mechanism of the oxidation of divalent iron and manganese by iron bacteria developing in a neutral acidic medium]. 3 22

Paraquat, a herbicide which is known to increase intracellular levels of superoxide anion (O2-), stimulated guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2.] activity. This stimulation by paraquat was seen at concentrations as low as 0.005 mM. The activation of guanylate cyclase by paraquat was not blocked by KCN, an inhibitor of superoxide dismutase [EC 1.15.1.1.], suggesting that the activation process probably does not involve superoxide dismutase which converts superoxide anion to hydrogen peroxide and ultimately to hydroxyl radical. Catalase [EC 1.11.1.6.] did not block the paraquat activation of guanylate cyclase indicating that hydrogen peroxide was probably not involved in the activation process. Butylated hydroxytoluene, a hydroxyl radical scavenger, also had no effect on the paraquat activation of guanylate cyclase activity. Superoxide dismutase inhibited the paraquat activation of guanylate cyclase. Thus, it would appear that superoxide ion itself can activate guanylate cyclase circumventing any requirement for hydroxyl radical formation.
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PMID:Activation of liver guanylate cyclase by paraquat: possible role of superoxide anion. 3 15

Oxidation of hypotaurine to taurine is known to occur in vivo. Search for an enzyme performing that oxidation has been unsuccessful. However, fast and quantitative oxidation of hypotaurine (and other sulfinates) by ultraviolet irradiation has now been observed. The reaction is first order and pH-dependent, and its rate depends strongly on the kind of sulfinate irradiated. Only the corresponding sulfonate is recovered as the product under the relatively mild conditions used. Catalase or superoxide dismutase does not affect the oxidation, which is oxygen-dependent. A simple reaction scheme is proposed to account for the findings.
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PMID:Oxidation of hypotaurine to taurine by ultraviolet irradiation. 3 3

Catalase (E.C. 1.11.1.6) activity and NADPH-dependent lipid peroxidation have been measured in liver microsomes from normal and acatalasemic mice. The absence of lipid peroxidation in acatalatic microsomes is not restituted by exogenous catalase as is microsomal methanol oxidation nor is it inhibited by sodium azide, thus suggesting an additional abnormality in these mice.
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PMID:Absence of microsomal lipid peroxidation in acatalasemic mice. 3 20


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