Carboxypeptidase-E（CPE ) is a carboxypeptidase that cleaves C-terminal amino acid residues and is involved in the biosynthesis of peptide hormones and neurotransmitters， including insulin. CPE is a peripheral membrane protein. CPE specifically connects regulated secretory pathway proteins， including prohormones， but constitutively secreted proteins. Mutations in CPE are implicated in type II diabetes.
