Animal DNA‐Dependent RNA Polymerases

Abstract

This paper describes a large‐scale method for the solubilization and the separation of calf thymus A and B DNA‐dependent RNA polymerase activities. This method is reproducible, gives high yields and can handle up to several kg of tissue. The solubilization method involved homogenization of the whole tissue, sonication at high ionic strength, ammonium sulphate precipitation and protamine sulphate precipitation to remove nucleic acids. The separation of the two types of activities A (insensitive to α‐amanitin) and B (inhibited by this compound) was achieved by differential adsorption to DEAE‐cellulose using a batch procedure. Studies of the inhibitory effect of α‐amanitin on the various fraction during the solubilization and the separation stages suggest very strongly that the two types of activities pre‐existed in vivo and did not result from the solubilization procedure.