Wikipedia
Surugatoxin (SGTX) is a type of venom found in the mid-gut digestive gland of the Japanese ivory mollusk Babylonia japonica, a carnivorous gastropod. It functions as a ganglionic blocker of nicotinic acetylcholine receptors (nAChRs). The structurally and functionally related neosurugatoxin, also derived from Babylonia japonica, is an even more potent nAChR antagonist than SGTX.
SGTX is a colorless crystalline substance with the chemical formula CHBrNO and a molecular weight of 684.4g/mol. Its systematic chemical name is [(2R,3S,5S,6S)-2,3,4,5,6-pentahydroxycyclohexyl] (6aS,7R,8R,9R)-6'-bromo-6a,9-dihydroxy-9-methyl-1,2',3,10-tetraoxo-spiro[4,5,6,7-tetrahydropyrido[1,2-f]pteridine-8,3'-indoline]-7-carboxylate. It is insoluble in organic solvents and has very low solubility in water.
The ganglionic blockade of nAChRs by SGTX is similar to that of IS-toxin, a structurally similar compound derived from the same mollusk, Babylonia japonica.