Large scale preparation of calf liver nuclei by continuous flow centrifugation

Summary Large scale purification and preparation of calf liver nuclei was accomplished by high speed centrifugation of a fraction enriched in nuclei (nuclear homogenate) through 1.8 M sucrose by means of a Beckman CF-32 Ti continuous flow rotor. In comparison with methods involving the use of conventional high capacity rotors, larger volumes of homogenate could be processed. This method was used to prepare nuclei from calf liver for the preparation of DNA-dependent RNA polymerases. The use of continuous flow ultracentrifugation avoids time-consuming manipulations, thus allowing handling of large quantities of tissue.Acknowledgments. The authors wish to thank Professor J. Brachet for his interest and fruitful discussion. They also thank Ms J. Gilder for secretarial assistance.