Phomopsin A

Isolated from Phomopsis leptostromiformis. White solid. Soluble in DMSO (10mg/ml), ethanol, methanol (5mg/ml) or DMF. Macrocyclic heptapeptide mycotoxin. Potent anti-mitotic compound that can cause cell death. Microtubule assembly inhibitor. Binds selectively to dimeric tubulin, inhibiting the formation of the microtubule spindle to block cell division. Binds at a site different from the colchicine binding site and overlapping the vinblastine binding site. Inhibits tubulin-dependent GTP hydrolysis. Binds ?-tubulin from higher organisms but not ?-tubulin or fungal mycelial tubulin. Causes lupinosis (a degenerative disorder) in livestock fed infected lupins.