Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

The enzyme horseradish peroxidase (EC 1.11.1.7) catalyses oxidation of NADH. NADH oxidation is prevented by addition of the enzyme superoxide dismutase (EC 1.15.1.1) to the reaction mixture before adding peroxidase but addition of dismutase after peroxidase has little inhibitory effect. Catalase (EC 1.11.1.6) inhibits peroxidase-catalysed NADH oxidation when added at any time during the reaction. Apparently the peroxidase uses hydrogen peroxide (H2O2) generated by non-enzymic breakdown of NADH to catalyse oxidation of NADH to a free-radical, NAD., which reduces oxygen to the superoxide free-radical ion, O2 (.-). Some of the O2 (.-) reacts with peroxidase to give peroxidase compound III, which is catalytically inactive in NADH oxidation. The remaining O2 (.-) undergoes dismutation to O2 and H2O2. O2 (.-) does not react with NADH at significant rates. Mn(2+) or lactate dehydrogenase stimulate NADH oxidation by peroxidase because they mediate a reaction between O2 (.-) and NADH. 2,4-Dichlorophenol, p-cresol and 4-hydroxycinnamic acid stimulate NADH oxidation by peroxidase, probably by breaking down compound III and so increasing the amount of active peroxidase in the reaction mixture. Oxidation in the presence of these phenols is greatly increased by adding H2O2. The rate of NADH oxidation by peroxidase is greatest in the presence of both Mn(2+) and those phenols which interact with compound III. Both O2 (.-) and H2O2 are involved in this oxidation, which plays an important role in lignin synthesis.
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PMID:Lignin synthesis: The generation of hydrogen peroxide and superoxide by horseradish peroxidase and its stimulation by manganese (II) and phenols. 2441 65