The platelet integrin receptoraIIbb3 plays a critical role in thrombosis and haemostasis by mediating interactions between platelets and several ligands but primarily fibrin-ogen. It has been shown previously that the YMESRADR KLAEVGRVYLFL (313–332) sequence of theaIIb subunit plays an important role in platelet activation, fibrinogen binding andaIIbb3 -mediated outside-in signalling. Further-more, we recently showed that the 20-residue peptide (20-mer) aIIb 313–332, is a potent inhibitor of platelet aggregationandfibrinogenbindingtoaIIbb3, interactingwith fibrinogen rather than the receptor
