Comparative characterization of two toxic phospholipases A2 from Indian cobra (Naja naja naja) venom.

Indian cobra venom contains many phospholipase A2 (PLA2) toxins. In the present study two toxic PLA2s have been purified from the Indian cobra (Naja naja naja) venom by column chromatography. The NN-XIa-and NN-XIb-PLA2s have mol. wts between 10,700 and 15,000. The NN-XIa-PLA2 induces myotoxic effects, oedema and neurotoxicity in mice and has an i.p. LD50 of 8.5 mg/kg body weight. The NN-XIa-PLA2 is also cytotoxic to Ehrlich ascites tumour cells. The other PLA2, NN-XIb, in contrast has an i.p. LD50 of 0.22 mg/kg body weight, and it induces acute neurotoxicity. The NN-XIb-PLA2 is devoid of the other biological activities which are exhibited by NN-XIa-PLA2.