Open AccessPrimary Structure of Peptides Released during Activation of Human Plasminogen by Urokinase
Author(s) -
Wiman Björn
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb03096.x
Subject(s) - cyanogen bromide , plasmin , chemistry , peptide , urokinase , lysine , cleavage (geology) , residue (chemistry) , amino acid , biochemistry , peptide sequence , amino acid residue , methionine , stereochemistry , peptide bond , protein primary structure , enzyme , biology , paleontology , genetics , fracture (geology) , gene
Activation of human plasminogen by urokinase is a two‐stage process. Initially peptide material is released from the NH 2 ‐terminal part of the proenzyme during formation of an inactive intermediate compound, from which plasmin is formed in a second step by proteolytic cleavage of an internal peptide bond. The released peptide material is shown to consist of two peptides, API and APII, containing 63 and 5 amino acid residues, respectively. The amino acid sequences of these peptides, and of two cyanogen bromide fragments situated in the NH 2 ‐terminal part of the plasminogen molecule (CNBr II and CNBr III), have been determined. From these results it is shown that API and APII, in intact plasminogen, occupy the positions 1–63 and 64–68 respectively. The residue in position 69 is shown to be methionine, which also is the NH 2 ‐terminal amino acid found in the intermediate compound formed during activation.