Peptidase family M3, dipeptidyl carboxypeptidase (DCP)
Peptidase family M3 dipeptidyl carboxypeptidase (DCP; Dcp II; peptidyl dipeptidase; EC 3.4.15.5). This metal-binding M3A family also includes oligopeptidase A (OpdA; EC 3.4.24.70). DCP cleaves dipeptides off the C-termini of various peptides and proteins, the smallest substrate being N-blocked tripeptides and unblocked tetrapeptides. DCP from Escherichia coli is inhibited by the anti-hypertensive drug captopril, an inhibitor of the mammalian angiotensin converting enzyme (ACE, also called peptidyl dipeptidase A). OpdA may play a specific role in the degradation of signal peptides after they are released from precursor forms of secreted proteins. It can also cleave N-acetyl-L-Ala. This family also includes Arabidopsis thaliana organellar oligopeptidase OOP (At5g65620), which plays a role in targeting peptide degradation in mitochondria and chloroplasts; it degrades peptide substrates that are between 8 to 23 amino acid residues, and shows a weak preference for hydrophobic residues (F/L) at the P1 position.