Pepsin catalytic domain (IPR034162)

Short name: Pepsin_A

Overlapping homologous superfamilies

Domain relationships


Pepsins, well-known aspartic endopeptidases, are produced by gastric mucosa of chordates and are classified by MEROPS as members of peptidase family A1 (pepsin A, clan AA) [PMID: 7674916]. There are several genes encoding pepsin-like gastric endopeptidases in humans, including pepsins A (MEROPS identifier A01.001), A4 (A01.070) and A5 (A01.071), and chymosin (formerly known as rennin; A01.006). A pepsin-like protein is also secreted by the chicken embryo (embryonic pepsin, A01.028). The prosequence of the zymogens are self-cleaved under acidic pH. Pepsins play an integral role in the digestion process of vertebrates. Pepsins specifically cleave bonds in peptides which have at least six residues in length with hydrophobic residues in both the P1 and P1' positions. The active site is located at the groove formed by the two lobes, with an extended loop projecting over the cleft to form an 11-residue flap, which encloses substrates and inhibitors in the active site. Specificity is determined by nearest-neighbour hydrophobic residues surrounding the catalytic aspartates, and by three residues in the flap [PMID: 2217165].

Contributing signatures

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