d-Amino Acid Oxidase

Abstract

Abstract The d-amino acid oxidase-catalyzed conversion of d-phenylglycine to benzoylformic acid can be followed spectrophotometrically by measuring the increase in optical density at 252 mµ which accompanies this reaction. Various properties of this d-phenylglycine reaction were studied, and conditions are given for the application of this reaction as a spectrophotometric assay of d-amino acid oxidase. Several previously established properties of d-amino acid oxidase were redetermined with the spectrophotometric method, and the results obtained were in good agreement with those previously observed with other assay methods. The spectrophotometric method was used to study the binding of pyridine carboxylic acid derivatives to the enzyme. The three isomeric pyridine carboxylic acids and N-methyl-nicotinic acid effectively inhibit d-amino acid oxidase, and the inhibition observed was in each case competitive with respect to substrate. Inhibitor dissociation constants are listed for the derivatives studied.