Carboxypeptidase A6 (IPR033843)

Short name: CPAH

Overlapping homologous superfamilies


Domain relationships


Carboxypeptidase (CP) A6 (CPA6, also known as CPAH; MEROPS identifier M14.018; EC:, belongs to the carboxypeptidase A/B subfamily of the M14 family of metallocarboxypeptidases (MCPs). The M14 family are zinc-binding CPs which hydrolyze single, C-terminal amino acids from polypeptide chains, and have a recognition site for the free C-terminal carboxyl group, which is a key determinant of specificity. CPA6 prefers large hydrophobic C-terminal amino acids as well as histidine, while peptides with a penultimate glycine or proline are very poorly cleaved.

Several neuropeptides are processed by CPA6, including Met- and Leu-enkephalin, angiotensin I, and neurotensin. CPA6 converts enkephalin and neurotensin into forms known to be inactive toward their receptors, but converts inactive angiotensin I into the biologically active angiotensin II. Thus, CPA6 plays a possible role in the regulation of neuropeptides in the extracellular environment within the olfactory bulb where it is highly expressed [PMID: 18178555]. It is also broadly expressed in embryonic tissue, being found in neuronal tissues, bone, skin as well as the lateral rectus eye muscle [PMID: 15950771]. A disruption in the CPA6 gene is linked to Duane syndrome, a defect in the abducens nerve/lateral rectus muscle connection [PMID: 12454025]. Mutations in the CPA6 gene have been identified in patients with epilepsy [PMID: 25875328].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0004181 metallocarboxypeptidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.