Maitotoxin

Maitotoxin or MTX is an extremely potent toxin produced by Gambierdiscus toxicus, a dinoflagellate species partially responsible for the phenomenon known as red tide. Maitotoxin has is so potent that it has been demonstrated that an intraperitoneal injection of 0.13 µg/kg was lethal in mice.

Maitotoxin activates Ca2+ permeable, non-selective cation channels, leading to an increase in levels of cytosolic Ca2+ ions. It is thought that maitotoxin leads to the formation of pores on these ion channels. Ultimately, a cell death cascade is activated, resulting in membrane blebbing and eventually cell lysis.

The molecule itself exists as a system of 32 fused rings. It is notable because it is one of the largest, and most complex, non-protein molecules produced by an organism. Its structure was established through analysis using nuclear magnetic resonance at Tohoku University, Harvard and the University of Tokyo.