Carboxypeptidase E (CPE)

Carboxypeptidase E cleaves C-terminal amino acid residues and is involved in neuropeptide processing. It is a peripheral membrane protein. CPE specifically binds regulated secretory pathway proteins, including prohormones, but not constitutively secreted proteins. Carboxypeptidase E is found in neuroendocrine cells and in adrenal gland chromaffin cells. The glycoprotein can be both membrane-associated or soluble. At the C-end of the molecule lies an amphiphilic α-helix which might be responsible for the membrane localisation. Carboxypeptidase E is found in all species of vertebrates that have been examined, and is also present in many other organisms that have been studied . Interesting, carboxypeptidase E is not found in the fruit fly, and another enzyme fills in for carboxypeptidase E in this organism.