An improved method for the preparation of the DNA-dependent RNA polymerase B from calf thymus.

A simplified method is described for the large-scale preparation of a highly purified DNA-dependent RNA polymerase B from calf thymus. The method includes homogenization and lysis of the tissue, chromatography on DEAE-cellulose, phosphocellulose, hydroxylapatite-Sephadex G-10 and, once again, phosphocellulose. The procedure avoids the preparation of nuclei, the use of sonication, ammonium sulphate precipitations and dialysis steps and needs no ultracentrifugation.