Platelet antagonist that specifically and reversibly binds to a site on platelet glycoprotein Ibalpha (GP1BA) close to or identical with the site for vWF binding. It inhibits the binding of vWF to platelets and vWF-dependent shear-induced platelet aggregation. Heterodimer of subunits alpha and beta; disulfide-linked. Expressed by the venom gland. Belongs to the snaclec family.