when unfractionated tubulin ( defined as material containing tubulin and microtubule-associated proteins ) was polymerized at room temperature or 37 degrees c , either probe could be incorporated into microtubules , since the observed diffusion coefficient ( approximately 1.7 x 10 ( -8 ) cm2/s ) was much slower than that for either probe free in solution .
C0026045
microtubule-associated proteins
C0026046
microtubules