title: Stoichiometry of the vinblastine-induced self-association of calf brain tubulin.
abstract: The self-association of calf brain tubulin in PG buffer (10(-2) M NaPi and 10(-4) M GTP, pH 7.0) induced by the antimitotic drug vinblastine has been investigated by velocity sedimentation. Schlieren sedimentation patterns were examined at low vinblastine concentrations where the boundary resolves into a bimodal one and at high vinblastine concentration where a single forward-skewed peak prevails. Weight-average sedimentation coefficients of tubulin were determined as a function of protein concentration, the results fitting well a self-association model of an idefinite isodesmic mechanism. This was confirmed by computer simulation of the sedimentation boundary profiles.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D008024:Ligands; D008433:Mathematics; D008954:Models, Biological; D011108:Polymers; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism*; D014461:Ultracentrifugation; D014747:Vinblastine / Q000494:pharmacology*
chemical_list: D008024:Ligands; D011108:Polymers; D014404:Tubulin; D014747:Vinblastine