Snake venom phospholipase A2 (PLA2) that causes irreversible neuromuscular blockade in chick biventer cervicis muscle preparations. The neuromuscular blockade is mediated by inhibitory action at the presynaptic motor nerve endings. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) Binds 1 Ca(2+) ion. Expressed by the venom gland. Does not show myotoxicity. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily.