PURIFICATION AND SOME PROPERTIES OF 2 PHOSPHOLIPASES AND A TOXIN FROMTHE VENOM OF DESERT COBRA (WALTERINNESIA-AEGYPTIA)

An acidic and a basic phospholipase A (PLA) and a toxin have been puri fied from the venom of W. aegyptia using a TSK G 3000 SW gel filtratio n column and a Mono Q ion-exchange column. Both phospholipases and the toxin were found to be in a homogeneous state on SDS-PAGE and their p urity was verified by isoelectric focusing. The acidic PLA showed high er enzymatic activity and concentration in venom when compared to basi c PLA. The acidic and the basic PLA showed 16.5+/-0.5 Kd and 14.5+/-0. 5 Kd molecular weights respectively, while the toxin showed 12.0+/-0.5 Kd molecular weights on SDS-PAGE. The isoelectric points for the acid ic and basic PLA were at pH 4.5 and 7.8 respectively. The toxin was fo cused in the basic region at pH 10. Both phospholipases constitute abo ut 20% of the venom protein and were nontoxic. However, only basic PLA when mixed with the toxin reduced the time required by the toxin alon e to kill the mice, while the toxin was highly lethal to mice and its LD(50) was 0.4 mu g/g of body weight of mouse. The toxin showed no pho spholipase activity.