Exopeptidase that catalyzes the removal of dipeptide units (NH2-P2-P1-) from the free amino termini of oligopeptides and small proteins (PubMed:24598890, PubMed:8892831, PubMed:24827749). Peptide digestion is sequential and substrate recognition is non-specific, with the exception that Pro is not suitable as a P1 residue (PubMed:24827749). Removes many residues of bioactive oligopeptides such as angiotensin I and neuromedin N and cleaves also oxidized insulin B chain. Able to hydrolyze an X-Pro bond, an imido bond. No endopeptidase activity (PubMed:8892831). May play a physiological role in feeding (PubMed:24598890). Completely inhibited by the serine protease inhibitor diisopropyl fluorophosphate (DFP) and potently inhibited by 0.5 mM ZnCl(2), 10 mM o-phenanthlorine, phenylmethanesulfonyl fluoride (PMSF) and N-tosyl-L-phenyl-alanyl chloromethyl ketone (TPCK), but not by N-tosyl-L-lysyl chloromethyl ketone (TLCK). Activity is not affected significantly by protease inhibitors, such as chymostatin, leupeptin, N-ethylmaleimide (NEM), iodoacetate (IAA), L-trans-epoxysuccinyl-leucylamido(4-guanido)butane (E64) and pepstatin A or by CoCl(2), CaCl(2) and EDTA. Optimum pH is 8 for the hydrolysis of Gly-Phe-pNA. Optimum temperature is approximately 30 degrees Celsius for the hydrolysis of Gly-Phe-pNA. Stable at a temperature below 20 degrees Celsius for 30 minutes. Homodimer. The chymotrypsin fold (25-276 and 574-722) is the catalytic domain and the alpha-helical domain (277-573) is the regulatory domain necessary for exopeptidase activity. Designing engineered forms of this protein with the ability to produce custom dipeptides potentially may have a number of commercial and industrial uses including food industry (PubMed:8892831, PubMed:24827749). Maybe useful for drug design (PubMed:24827749). Belongs to the peptidase S46 family.