COMPARISON OF SEDIMENTATION PROPERTIES OF MICROTUBULE PROTEIN OLIGOMERS PREPARED BY 2 DIFFERENT PROCEDURES

Previously reported values of 30S and 36S for the sedimentation coefficients of [porcine brain] microtubule protein oligomers prepared by 2 different methods (Borisy et al. and Weingarten et al.) and analyzed under different conditions were confirmed. These differences in sedimentation coefficients were also observed when the 2 classes of oligomers were analyzed under the same conditions, both at 5.degree. C in the absence of Ca2+ and at 24.5.degree. C in the presence of Ca2+. Gel electrophoresis showed differences in composition, the principal difference being a reduced amount of some high MW (3 .times. 105 Daltons) proteins in the samples prepared by the Weingarten et al. method. The 2 procedures produce genuine differences in the properties of microtubule protein.