Figure 3.

Dependence of subtilisin digestion on vinblastine concentration. Tubulin (2 mg/ml) was preincubated with different concentrations of vinblastine at 25°C for 25 min followed by subtilisin (1:100) digestion for 50 min. After addition of 1% phenylmethylsulfonyl fluoride, samples were electrophoresed on SDS/10% gels. (Top) Coomassie stain. (Middle) Fraction of tubulin as native or digested monomers. (Bottom) Comparison of turbidity (○) and 90° light scattering (•) under the same conditions.