May be involved in the proteolytic inactivation of enkephalins and neurotensin in some brain areas. May convert inactive angiotensin I into the biologically active angiotensin II (PubMed:18178555). Releases a C-terminal amino acid, with preference for large hydrophobic C-terminal amino acids and shows only very weak activity toward small amino acids and histidine (PubMed:20855895). Binds 1 zinc ion per subunit. Optimum pH is 8. Expressed in the hippocampus, nucleus raphe, and cortex. A chromosomal aberration involving CPA6 was found in a patient with Duane retraction syndrome. Translocation t(6;8)(q26;q13). The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. May be due to intron retention. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the peptidase M14 family. Wrong choice of CDS.