The oxidation of Schiff bases of pyridoxamine with  -oxo acids by manganous ions and peroxidase.
1. Oxygen was taken up rapidly when pyruvate was added to mixtures of pyridoxamine and Mn(2+) ions after lag periods that were shortened by peroxidase (donor-hydrogen peroxide oxidoreductase, EC 1.11.1.7). 2. The total oxygen uptake was proportional to the pyridoxamine added and was accompanied by the disappearance of pyridoxamine; the pyruvate acted catalytically and hydrogen peroxide was not formed. 3. At pH6 more than half the pyridoxamine that disappeared was accounted for as pyridoxal and ammonia; it is suggested that the primary reaction is the oxidative deamination of the pyridoxamine. 4. Results were similar when alpha-oxobutyrate or glyoxylate were substituted for pyruvate, except that the reactions were slower and the yield of pyridoxal less. 5. The oxidative decarboxylations of alpha-oxoglutarate and phenylpyruvate are catalysed by Mn(2+) ions and these reactions are activated by peroxidase; pyridoxamine increased both the rates and total oxygen uptakes in these reactions, and ammonia was produced. 6. The lag periods in the oxidation of mixtures of pyridoxamine and alpha-oxo acids, catalysed by Mn(2+) ions, were also shortened by traces of colloidal manganese dioxide. 7. It is suggested that the activating effect of peroxidase depends on its catalysis of manganese oxidation.
D000641:Ammonia; D002087:Butyrates; D002384:Catalysis; D003641:Deamination; D003653:Decarboxylation; D005977:Glutarates; D006038:Glyoxylates; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D007651:Keto Acids; D008345:Manganese; D010084:Oxidation-Reduction; D010544:Peroxidases; D010667:Phenylpyruvic Acids; D010847:Picolines; D011730:Pyridoxal; D011733:Pyridoxamine; D011736:Pyridoxine; D011773:Pyruvates; D012545:Schiff Bases; D013053:Spectrophotometry; D013997:Time Factors
D002087:Butyrates; D005977:Glutarates; D006038:Glyoxylates; D007651:Keto Acids; D010667:Phenylpyruvic Acids; D010847:Picolines; D011773:Pyruvates; D012545:Schiff Bases; D011730:Pyridoxal; D008345:Manganese; D011733:Pyridoxamine; D000641:Ammonia; D006861:Hydrogen Peroxide; D010544:Peroxidases; D011736:Pyridoxine