IN-VIVO DEGRADATION OF HUMAN FIBRINOGEN A-ALPHA - DETECTION OF CLEAVAGE SITES AND RELEASE OF ANTITHROMBOTIC PEPTIDES

Several degradation products of fibrinogen have been shown to possess regulatory functions. Using peptide exacts from human blood filtrate, a large number of fibrinogen A alpha fragments was identified. These f ragments are generated at known plasmin attack sites and at several no vel cleavage sites especially at hydrophobic and basic amino acid resi dues. One fragment containing the cell attachment site (RGD sequence) of fibrinogen A alpha efficiently inhibits fibrinogen binding and plat elet aggregation (IC50: 20-50 mu M) in vitro. We conclude that in vivo degradation of fibrinogen A alpha. results in generation of endogenou s antithrombotic peptides with local importance in fibrinolysis and pl atelet aggregation. (C) 1995 Academic Press, Inc.