Snake venom phospholipase A2 (PLA2) that produces neuromuscular blockade in chick biventer cervicis preparations in the absence and presence of crotapotin. In contrast, in mouse phrenic nerve-diaphragm preparations, the neuromuscular blockade is dependent on crotapotin. 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. Pre-incubation with heparin markedly reduces the neurotoxicity of this toxin. Optimum pH is 7.9. Optimum temperature is 25 degrees Celsius. Expressed by the venom gland. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily.