title: Successive cleavage of N-terminal Arg1--Pro2 and Lys3-Pro4 from substance P but no release of Arg1-Pro2 from bradykinin, by X-Pro dipeptidyl-aminopeptidase.
abstract: X-Pro dipeptidyl-aminopeptidase (EC 3.4.14.1) purified homogeneously from the human submaxillary gland was proved to hydrolyze N-terminal dipeptide Arg1-Pro2 and subsequent dipeptide Lys3-Pro4 from substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-gly-Leu-Met-NH2). Km and V values of hydrolysis of substance P were 2.0 mM and 3.6 mumol/min per mg protein, respectively. In contrast, the N-terminal Arg-Pro of bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) was not cleaved by the enzyme.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001920:Bradykinin; D002403:Cathepsins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D013373:Substance P; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D013373:Substance P; D002403:Cathepsins; D001920:Bradykinin