Heterodimer: postsynaptic neurotoxin. Monomer: Acidic phospholipase A2 homolog that is non-toxic. Heterodimer of A and B (AC P14420) chains; non-covalently linked. The A chain (acidic) is non-toxic, and increases the toxicity of the B chain (basic). The A chain may act as factor stabilizing the complex structure and hence retaining its toxicity by preventing non-specific binding. Upon binding to the target membranes the A chain may dissociate. Expressed by the venom gland. Heterodimer: LD(50) is 0.7-1.2 mg/kg by intraperitoneal injection into mice and 0.9-1.3 mg/kg by intravenous injection into mice. Heterodimer: LD(50) is 0.9-1.3 mg/kg by intravenous injection into mice. Monomer: LD(50) is >30 mg/kg by intraperitoneal injection into mice. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily. In contrast to other phospholipases, it lacks the typical His active site (His->Gln in position 47). The acidic chain was originally postulated to act as an inhibitor of the basic chain.