D-Amino Acid Oxidase in Leukocytes: A Possible D-Amino-Acid-Linked Antimicrobial System

D-Amino acid oxidase has been identified within the granule fraction of human neutrophilic leukocytes. Leukocyte homogenates and purified kidney D-amino acid oxidase can utilize either isolated D-amino acids or some species of bacteria as substrates for the generation of hydrogen peroxide. When linked to leukocyte myeloperoxidase in vitro, purified D-amino acid oxidase constitutes a system lethal for certain bacteria. It is proposed that leukocyte D-amino acid oxidase and myeloperoxidase constitute a biochemically specific system for the recognition and killing of certain microorganisms.