Vinblastine-induced precipitation of microtubule protein.

Vinblastine quantitatively precipitates a protein from supernatants obtained from high-speed centrifugation of homogenates of HeLa cells and of pig brain. This protein migrates as a single band on gel electrophoresis, has a mobility identical to that of purified microtubule protein, and-like microtubule protein-binds colchicine. The precipitation is partially inhibited by 0.9 percent NaCl.