Isolation and purification of superbins I and II from Austrelaps superbus (copperhead) snake venom and their anticoagulant and antiplatelet effects

Abstract

Two proteins with anticoagulant and antiplatelet activities were purified from Austrelaps superbus (copperhead) venom by gel filtration, ion-exchange and reverse-phase chromatographic methods. These purified proteins were designated superbins I and II. Superbin I was homogeneous, as indicated by electrospray ionization-mass spectrometry, with a mol. wt of 13,252.3 +/- 1.6, whereas superbin II contained two closely related proteins of mol. wts 13,235.5 +/- 1.1 and 13,212.9 +/- 1.2. Both superbins showed phospholipase A2 activity and exhibited weak anticoagulant effects when tested by one-step prothrombin time clotting assays. The 'dissection approach' was used to identify the coagulation complex(es) inhibited by these enzymes in the extrinsic coagulation cascade. The results indicate that both the enzymes inhibit the extrinsic tenase complex, but not the prothrombinase complex, similarly to other weakly anticoagulant phospholipases. Superbins I and II also inhibited aggregation of human platelets induced by collagen.