Distribution of D-aspartate oxidase and free D-glutamate and D-aspartate in chicken and pigeon tissues

1. The presence of D-aspartate oxidase activity and D-glutamate was demonstrated for the first time in several tissues of chicken and pigeon. 2. The identification of the enzyme was based on substrate and inhibitor specificity of the activity as well as other requirements for the activity, and the amino acid was identified with HPLC analysis. 3. In each animal, the highest activity was found in the kidney. In chicken, the hepatic, renal and pancreatic activities were significantly higher in male than female. In pigeon, however, any significant gender difference was not observed. 4. A substantial amount of D-glutamate, as well as D-aspartate, was detected in each tissue, irrespective of species. 5. The contents of the free D-enantiomers were significantly different between two genders in the chicken kidney, heart and pancreas and pigeon liver and kidney. However, any common relationship was not observed between the contents and the D-aspartate oxidase activity.