Abstract
Two major peaks of RNA polymerase activity have been routinely separated by diethylaminoethyl cellulose chromatography following solubilization from soybean (Glycine max L. var. Wayne) chromatin. The relative amounts of these two peaks depend upon the manner in which the chromatin is purified. Pelleting the chromatin through dense sucrose solutions results in not only a loss of total solubilized RNA polymerase activity but also a selective loss of the alpha-amanitin-sensitive form of the enzyme. Peak I elutes from a diethylaminoethyl cellulose column at a KCl concentration of approximately 0.27 m, is insensitive to alpha-amanitin and rifamycin, and has Mg(2+) + Mn(2+) optima of 5 mm and 1.25 mm, respectively. The enzyme is inhibited by KCl concentrations of about 0.03 m or greater. Peak II elutes from the column at a KCl concentration of approximately 0.35 m, is sensitive to alpha-amanitin, insensitive to rifamycin, and has Mg(2+) + Mn(2+) optima of 2 mm and 1.0 mm, respectively. Activity is inhibited by KCl concentrations of about 0.06 m or greater. Both enzymes prefer denatured calf thymus DNA, but peak II exhibits a stronger preference.