Heterotrimer: Snake venom phospholipase A2 (PLA2) that has presynaptic neurotoxicity. Inhibits nerve-evoked twitch contractions but not responses to cholinergic agonists acetylcholine and carbachol and to depolarizing agonist KCl. Causes a fade in tetanic contractions. Displays a triphasic mode of action with depression, enhancement and blockade of neurotransmission. Does not display myotoxic activity such as changes in baseline muscle tension or inhibition of directly stimulated muscle twitches. All subunits are necessary for maximum toxicity. Monomer: the gamma chain has no significant enzymatic activity and is not toxic by itself. Heterotrimer of alpha, beta and gamma chains, each related to PLA2. Expressed by the venom gland. Glycosylated. glycosylated form. glycosylated form. glycosylated form. Preincubation of P-elapitoxin-Aa1a with monovalent antivenom or suramin prevents or delays toxicity, respectively. Antivenom fails to reverse neurotoxicity when applied at point of 90% neuromuscular blockade. Treatment of P-elapitoxin-Aa1a with 4-bromophenacyl bromide drastically reduces enzymatic activity and toxicity, presumably by alkylating a His residue at the active site. Belongs to the phospholipase A2 family. Group I subfamily.