| pepsin | <protein> Acid protease from stomach of vertebrates. Cleaves preferentially between two hydrophobic amino acids (e.g. F L, F Y) and will attack most proteins except protamines, keratin and highly glycosylated proteins. A single chain phosphoprotein (327 amino acids, 34.5 kD) released from the enzymatically inactive zymogen, pepsinogen, by autocatalysis at acid pH in the presence of HCl. One of the peptides cleaved off in this process is a pepsin inhibitor and has to be further degraded to allow the pepsin to have full activity. (18 Nov 1997) |
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| pepsin a | <enzyme> Formed from pig pepsinogen by cleavage of one peptide bond. The enzyme is a single polypeptide chain and is inhibited by methyl 2-diaazoacetamidohexanoate. It cleaves peptides preferentially at the carbonyl linkages of phenylalanine or leucine and acts as the principal digestive enzyme of gastric juice. Pharmacological action: gastrointestinal agents. Registry number: EC 3.4.23.1 (12 Dec 1998) |