Agkisacutacin, a C-type lectin-like protein (CLP) isolated from Agkistrodon acutus venom. had been previously identified as,in antagonist of platelet aggregation induced by ristocetin, as well as a certain extent fibrinogenlytic activity. In this study, agkisacutacin was further purified by three-step chromatography, and its biological functions were characterized, Agkisacutacin after further purification retained the effect on ristocetin-induced, on Willebrand factor-dependent platelet aggregation. while it lost the fibrinogenlytic activity. FACS and ELISA assays showed that agkisacutacin belongs to membrane glycoprotein lb-binding protein (GPIb-bp) for it Could block and inhibit the binding of anti-GPIb antibody to GPIb. Especially, agkisacutacin exhibits anti-coagulant activity and the function as IX/X-binding protein was confirmed by PAGE and ELISA, So. agkisacutacin is the first reported CLP that binds to both platelet membrane receptors and coagulation factors. (c) 2005 Elsevier Inc. All rights reserved.