This cysteine-rich disintegrin (Mr = 8500) from the snake Bitis arietans contains an RGD loop that facilitates tight binding to integrins in a manner that inhibits platelet aggregation stimulated by ADP, thrombin, collagen, and U46619, with IC50 = 130-270 nM. At 65 nM, arietin blocks fibrinogen- induced aggregation of elastase-treated platelets.
