Binds with high affinity to muscular (alpha-1/CHRNA1) and neuronal (alpha-7/CHRNA7) nicotinic acetylcholine receptor (nAChR) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular and neuronal transmission (By similarity). Produces paralysis, clear dyspnea and lethality on mice (PubMed:9133710). Expressed by the venom gland. LD(50) is between 0.05 and 0.20 mg/kg by intraperitoneal injection into mice. These data should be viewed cautiously since only a few mice have been injected due to the low amount of toxin available. Exists in two forms which are separated by reverse-phase high-performance liquid chromatography, but which have the same sequence and molecular weight. The existence of cis and trans isomers may explain the two different elution peaks (PubMed:9133710). Belongs to the snake three-finger toxin family. Long-chain subfamily. Type II alpha-neurotoxin sub-subfamily.