Heterodimer RV-4/RV-7: acts as a presynaptic neurotoxin. Monomer: snake venom phospholipase A2 (PLA2) that acts as a presynaptic neurotoxin. 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. Heterodimer of a weakly toxic basic protein having phospholipase A2 activity (RV-4) and a non-toxic acidic protein which inhibits its enzymatic activity but potentiates its lethal potency and neurotoxicity (RV-7). Expressed by the venom gland. LD(50) is 0.32 mg/kg by intravenous injection for RV-4 and 0.15 mg/kg for RV-4/RV-7 complex. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily.