Heterotrimer: Snake venom phospholipase A2 (PLA2) heterotrimer that acts as a potent presynaptic neurotoxin by blocking synaptic transmission and synaptic vesicle recycling. May act by binding in a calcium-dependent fashion to neurotonal pentraxin-1 (NPTX1) and neurotonal pentraxin-2 (NPTX2), but not to neuronal pentraxin receptor (NPTXR). Also binds to taipoxin-associated calcium binding protein 49 (RCN2), a protein localized in the lumen of endoplasmic reticulum. Monomer (alpha chain): Snake venom phospholipase A2 (PLA2) alpha chain that possesses the same high enzymatic activity as the heterotrimer. 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. Heterotrimer of alpha, beta, and gamma chains; non-covalently linked. Expressed by the venom gland. Monomer (alpha chain): LD(50) is 0.3 mg/kg by intravenous injection into mice. Heterotrimer: LD(50) is 2 ug/kg by intravenous injection into mice. Belongs to the phospholipase A2 family. Group I subfamily. D49 sub-subfamily.