Carboxypeptidase B (EC 3.4.17.2) catalyzes hydrolysis of the basic amino acids lysine, arginine and ornithine from the C-terminal end of polypeptides. The Mw was found to be 34.5 kda, optimun pH 7.9, and pI-6. Carboxypeptidase B is inhibited by arginine, lysine and ornithine. The enzyme is not inhibited by di-isopropylfluorophosphate (DFP), but it is inhibited by metal chelating agents, e.g., EDTA, 1,10-phenanthroline Synonyms: Carboxypeptidase B, Cpb1, Cpb.