A New Peptide from the Venom of the Madagascar Cat-Eyed Snake Madagascarophis colubrinus Blocks Nicotinic Acetylcholine Receptor

Abstract— In screening the venoms of various snake species, we found that venom Madagascar cat-eyed Madagascarophis colubrinus competes with α-bungarotoxin for binding to nicotinic acetylcholine receptor from Torpedo californica . Using liquid chromatography, a peptide inhibits α‑bungartoxin this was isolated and named macoluxin. The amino acid sequence 23-amino determined by automatic Edman degradation. Comparison sequences known proteins showed macoluxin is homologous α-helical region metalloproteinases. synthesized solid-phase synthesis, study its biological activity it an IC 50 47 μM. Macoluxin also reversibly inhibited acetylcholine-induced currents in muscle-type receptor. This first data on presence can inhibit rear-fanged snakes.