Pepsin consists of a single polypeptide chain and arises from its precursor, pepsinogen, by removal of a 41 amino acid segment from the N-terminus. Pepsinogen is synthesized in the stomach lining, and hydrochloric acid, also produced by the gastric mucosa, is necessary to convert the inactive enzyme and to maintain the optimum acidity (pH 1-3) for pepsin function. Pepsin is particularly effective in cleaving peptide bonds involving aromatic amino acids. Pepsin shows extremely broad specificity; although bonds involving phenylalanine and leucine are preferred, many others are also cleaved to some extent. Pepsin A is a member of the subfamily A1 within the pepsin family and is the predominant endopeptidase in the gastric juice of vertebrates. Pepsin A is inhibited by ovUS-1, a uterine serpin.
pepsin A; Pepsin A-3; Pepsin A-4; Pepsin A-5; Pepsin F; pepsinogen 5, group I; pepsinogen 5, group I (pepsinogen A); pepsinogen A3; pepsinogen A4; pepsinogen A5; pepsinogen F; pepsinogen F protein; Pepsinogen-3; Pepsinogen-4; Pepsinogen-5