D-AMINO-ACID OXIDASE IS NOT PRESENT IN THE MOUSE-LIVER

Since there are conflict reports on the presence of D-amino-acid oxida se in the mouse liver, this problem was examined. D-Amino-acid oxidase activity was not detected in the homogenates of the mouse liver, lung , or heart, whereas it was detected in the homogenates of the mouse ki dney and brain. Western blotting showed that a protein which reacted w ith the antiserum against pig D-amino-acid oxidase was present in the homogenates of the mouse kidney and brain but not in those of the live r or heart. Northern hybridization using a D-amino-acid oxidase cDNA p robe detected a hybridizing signal in poly(A)(+) RNAs extracted from t he mouse kidney and brain but not in those from the liver, heart, or l ung. Reverse transcription-polymerase chain reaction using three prime r pairs always amplified D-amino-acid oxidase cDNA fragments of expect ed sizes in the mouse kidney and brain but very rarely did so in the l iver, heart, or lung. The results indicate that D-amino-acid oxidase i s not present in the mouse liver in a measurable amount.