Methods for the detection of D-amino-acid oxidase

Four methods (an enzyme activity assay, western blotting, RT-PCR, and northern hybridization) to detect the enzyme D-amino-acid oxidase are described. D-Amino-acid oxidase catalyzes oxidative deamination of D-amino acids (stereoisomers of naturally occurring L-amino acids) to the corresponding 2-oxo acids, producing ammonia and hydrogen peroxide in the course of the reaction (1). This enzyme is present in a wide variety of organisms (2). However, the physiological role of this enzyme has been unclear because its substrate D-amino acids have been considered to be rare in eukaryotic organisms (2, 3). In previous work, my colleagues and I concluded that D-amino-acid oxidase is not present in the mouse liver (13). This paper examines in greater detail the methods used in reaching that conclusion. ©1998 Biological Procedure Online. All rights reserved.