Two spectrophotometric assays for D-amino acid oxidase: for the study of distribution patterns.

1. Two simple, rapid and sensitive methods are described for measurement of D-amino acid oxidase (DAO) activity using crude tissue extracts for the study of distribution patterns. 2. They detect products of oxidative deamination of D-amino acids catalyzed by DAO, i.e. alpha-keto acids and H2O2 by measuring light absorbances at 445 and 500 nm, respectively. 3. Reliability of the methods was confirmed by quantitative detection of DAO added to the tissue extract, based on standard curves, time courses and values of Km and Ki, obtained using D-Ala as substrate.