EXPERIMENTAL FIGURE 9-11 Liquid chromatography separates and identifies the three eukaryotic RNA polymerases, each with its own sensitivity to α-amanitin. A protein extract from the nuclei of cultured eukaryotic cells was passed through a DEAE Sephadex column and adsorbed protein eluted (black curve) with a solution of constantly increasing NaCl concentration. An aliquot of each fraction of eluate collected from the column was assayed for RNA polymerase activity without (red curve) and with (green shading) 1 µg/ml α-amanitin. This concentration of α-amanitin inhibits polymerase II activity but has no effect on polymerases I and III. Polymerase III is inhibited by 10 µg/ml of α-amanitin, whereas polymerase I is unaffected even at this higher concentration. See R. G. Roeder, 1974, J. Biol. Chem. 249:241.