Peptidase
A type of protease enzyme that specifically cleaves peptide bonds. Peptidases are classified as endopeptidases (which cut within the peptide chain) or exopeptidases (which remove amino acids from the ends). Understanding peptidase activity is critical for designing stable peptide drugs.
Technical Context
Peptidases are functionally classified as endopeptidases (cleaving internal bonds) and exopeptidases (cleaving terminal residues). Exopeptidases include aminopeptidases (N-terminal cleavage), carboxypeptidases (C-terminal cleavage), and dipeptidyl peptidases (removing dipeptides from the terminus). DPP-4 is a dipeptidyl aminopeptidase — it removes a dipeptide from the N-terminus of substrates with alanine or proline at position 2. Neprilysin (neutral endopeptidase) degrades several endogenous peptides including natriuretic peptides, bradykinin, and substance P. The collective activity of peptidases determines the metabolic fate and half-life of circulating peptide drugs.