Carboxypeptidase O (CPO)

By searching databases for sequences similar to CPA1 and CPB1, Wei et al. (2002) identified a partial CPO cDNA encoding a carboxypeptidase catalytic domain with all residues involved in zinc coordination and substrate catalysis. The predicted active site differs from that of other carboxypeptidases, and the enzyme likely cleaves C-terminal acidic amino acids.

Carboxypeptidase (EC number 3.4.16 - 3.4.18) is an enzyme that hydrolyzes the carboxy-terminal (C-terminal) end of a peptide bond. Humans, animals, and plants contain several types of carboxypeptidases with diverse functions ranging from catabolism to protein maturation.The first carboxypeptidases studied were those involved in the digestion of food (pancreatic carboxypeptidases A1, A2, and B). However, most of the known carboxypeptidases are not involved in catabolism; they help to mature proteins or regulate biological processes.