Differences in polypeptide composition and enzyme activity between cold-stable and cold-labile microtubules and study...

Cold-stable and cold-labile microtubules were prepared by two cycles of assembly and disassembly and two periods of exposure to cold. The cold-labile preparations were shown to contain a higher proportion of a high molecular mass microtubule-associated protein (MAP 2) than cold-stable preparations. The cold-stable preparations showed a much higher alkaline phosphatase activity. Stimulation of microtubule assembly by zinc led to increases in both cold stability and alkaline phosphatase activity.