PRELIMINARY CRYSTALLOGRAPHIC STUDY OF THE PLATELET AGGREGATION INHIBITOR FROM THE VENOM OF Agkistrodon halys Pallas

In addition to esterasic activity, phospholipase A2 （PLA2） from snake venom possesses various physiological activities and toxicities, such as hemolysis, anticoagulation, platelet function, presynaptic toxicity, muscular toxicity. It has been found that the venom from Agkistrodon halys Pallas has three homologous PLA2, which are quite different from each other in enzymatic activity, presynaptic toxicity, platelet function, hemolysis and anticoagulation. For example, the neutral PLA2 has strong presynaptic toxicity, but no platelet function. On the contrary, the acidic PLA2 can inhibit the platelet aggregation, but