A STUDY OF OPTIMAL CONDITIONS FOR SEPARATING PROTEIN FRACTIONS FROM ISOLATED CELL NUCLEI

A study has been made of the effect of changes in conditions used for the extraction of the globulin fraction of isolated cell nuclei on the ratios of the various nuclear protein fractions to DNA. It has been found that the ratio of total histone to DNA is maximal when the pH of globulin extraction is about 5.6 or the concentration of NaCl used for globulin extraction is 0.8% or both. Under these conditions the total histone to DNA ratio is about 2.5. As the pH of globulin extraction increases above 6.0, the ratios of total histone and residual protein to DNA fall rather rapidly, as does the concentration of DNA in the nuclei. The latter effects are thought to be attributable to increased proteolysis and nucleolysis as the pH of globulin extraction increases above 5.8. © 1969.