Purification and characterization of a potent hemolytic toxin with phospholipase A2 activity from the venom of Indian XXXX .

@entity1472 @entity137 @entity9115
A potent toxin with phospholipase A2 (PLA2) and hemolytic activity in vitro was purified from the @entity9115 venom of eastern India (RVV-EI). The purified protein (RVV-PFIIc') of 15.3 kDa molecular weight, and a lethal @entity137 dose (LD50i.p.) of 0.1 mg/kg body weight, was the most toxic PLA2 so far reported from the Indian subcontinent. The material also possessed anticoagulant activity as it enhanced the prothrombin induced plasma clotting time in vitro. The PLA2 toxin (RVV-PFIIc') was shown to be different from other PLA2s of RVV in respect to one or more of these parameters e.g. molecular weight, isoelectric pH, in vivo @entity137 , specific activity of the enzyme and certain other biological activities. The first 19 @entity1472 terminal sequence (NLFQFAEMIVKMTGKEAVH) of RVV-PFIIc' showed variable degree of homology (42.1-94.7%) with those of other RVV-PLA2s described in the literature. Antisera raised against RVV-EI or RVV-PFIIc', though completely neutralized the in vivo lethal @entity137 of RVV-EI or RVV-PFIIc', failed to inhibit their PLA2 activity in vitro thereby suggesting that in vivo @entity137 and in vitro activity of the enzyme may not be directly related. Apart from RVV-PFIIc', at least two other PLA2 isozymes were found to be present in RVV-EI that were distinct from RVV-PFIIc' in respect to their molecular, biological as well as serological properties. The significance of these and related data in antivenom therapy is discussed.
