Snake venom phospholipase A2 (PLA2) that shows presynaptic neurotoxicity. 10 ug/ml of this protein produce complete neuromuscular blockade up to 80 minutes, without inhibiting the responses to acetylcholine (ACh) and potassium chloride (KCl). In addition, it produces a calcium-dependent blockade of acetylcholine release and causes appearance of giant miniature end-plate potentials. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides