title: Involvement of D-amino-acid oxidase in D-amino acid utilization in the mouse.
abstract: Mutant ddY/DAO- mice lacking D-amino-acid oxidase were examined for their ability to utilize D-phenylalanine in place of its L-isomer. Chemically defined milk powder devoid of phenylalanine was used as a basal diet. Adult ddY/DAO- mice and normal ddY/DAO+ mice having D-amino-acid oxidase lost weight every day when fed this diet. However, they maintained their weight when fed the milk powder diet supplemented with 0.33% L-phenylalanine. Although adult ddY/DAO+ mice maintained their weight when fed the milk powder diet supplemented with 0.33% D-phenylalanine, ddY/DAO- mice lost weight while feeding on this diet, which indicated that the ddY/DAO- mice could not utilize D-phenylalanine in place of its L-isomer. Both ddY/DAO- and ddY/DAO+ mice maintained their weight when feeding on the milk powder diet enriched with 0.41% sodium phenylpyruvate, which suggested to us that the ddY/DAO- mice had the ability to invert this alpha-keto acid to L-phenylalanine. Therefore, these results indicate that D-amino-acid oxidase is indispensable for D-amino acid utilization. This is consistent with the concept that D-amino acids are oxidatively deaminated to the corresponding alpha-keto acids by D-amino-acid oxidase and that these keto intermediates are then asymmetrically reaminated to their L-amino acids.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D003605:D-Amino-Acid Oxidase / Q000235:genetics / Q000378:metabolism*; D004032:Diet; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation; D010084:Oxidation-Reduction; D010649:Phenylalanine / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D010649:Phenylalanine; D003605:D-Amino-Acid Oxidase