Abstract 2100 Carboxypeptidase O and glutamate carboxypeptidase II have redundant functions in C-terminal amino acid cleavage

Carboxypeptidases are enzymes that hydrolyze peptide bonds at the carboxyl ends of proteins and peptides, facilitating critical physiological events such as fibrinolysis, processing of neuropeptides and hormones, and immune response, among others. Carboxypeptidase O (CPO) is a recently discovered carboxypeptidase highly expressed in the human ileum and the brain, with a preference for cleaving acidic residues such as glutamate and aspartate. Although no definitive physiological function of CPO has been determined yet, its localization and substrate specificity are comparable to another enzyme, glutamate carboxypeptidase II (GCPII), which hydrolyzes glutamates from dietary folates in the ileum and cleaves N-Acetylaspartylglutamic acid (NAAG) in the brain.