Levels of RNA polymerases during the mitotic cycle of Physarum polycephalum.

Two RNA polymerase activities were quantitatively solubilized in plasmodial homogenates from Physarum polycephalum by sonication at 0.5 M ammonium chloride concentration. The proportions of RNA polymerases A and B were determined by four different methods. Equal activity levels of both enzyme A and enzyme B were detected throughout the synchronous mitotic cycle of Physarum.