D amino acid oxidase

D-amino acid oxidase (DAAO; also DAO, OXDA, DAMOX) is a peroxisomal enzyme containing FAD as cofactor that is expressed in a wide range of species from yeasts to human. It is not present in plants or in bacteria which instead use D-amino acid dehydrogenase. Its function is to oxidize D-amino acids to the corresponding imino acids, producing ammonia and hydrogen peroxide.

This enzyme belongs to the FAD dependent oxidoreductase family, and acts on the CH-NH₂ group of D-amino acid donors with oxygen as acceptor. The enzyme is most active toward neutral D-amino acids, and not active toward acidic D-amino acids.

Recently, mammalian D-amino acid oxidase has been connected to the brain D-serine metabolism and to the regulation of the glutamatergic neurotransmission. In a postmortem study, the activity of DAAO was found to be two-fold higher in schizophrenia.

DAAO is a candidate susceptibility gene and together with G72 may play a role in the glutamatergic mechanisms of schizophrenia. Risperidone and sodium benzoate are inhibitors of DAAO.

DAAO is used as a biocatalyst in several biotechnological applications, such as the oxidation of cephalosporin C, the deracemition of racemic D-amino acid solutions and as the biological component in several biosensors for the determination of the content in D-amino acids of biological fluids.

This protein may use the morpheein model of allosteric regulation.