Potency Difference between the Zwitterion Form and the Cation Forms of Tetrodotoxin

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Science  23 Jun 1967:
Vol. 156, Issue 3782, pp. 1625-1627
DOI: 10.1126/science.156.3782.1625


Tetrodotoxin can exist as a zwitterion or two different cations in aqueous solutions. The cation forms are more potent in nerve block. Thus the lactone-hemilactal configuration of tetrodotoxin influences potency. Electrostatic attraction, hydrogen bonding, and intermolecular hemilactal formation are possible mechanisms of interaction with membrane receptors.