Phomopsinamine is an inhibitor of microtubule polymerization and a derivative of phomopsin A .1It inhibits the rate and extent of polymerization of tubulin isolated from ovine brain (IC50s = 0.53 and 0.59 μM, respectively). 1.Lacey, E., Edgar, J.A., and Culvenor, C.C.Interaction of phomopsin A and related compounds with purified sheep brain tubulinBiochem. Pharmacol.36(13)2133-2138(1987)