Characterization of nuclear non-histone proteins from rat liver isolated in the polyethylene glycol-dextran system and separated by hydroxyapatite chromatography.

1. Three groups of non-histone proteins were obtained from rat liver nuclei by separation of nucleic acids with the polyethylene glycol - dextran polymer mixture and fractionation of nuclear proteins on hydroxyapatite in the salt - glycerol - phenylmethylsulphonyl fluoride system at increasing concentration of Na+ and K+ phosphate buffer, pH 6.8. 2. Non-histone proteins of rat liver represent a heterogeneous complex of polypeptides devoid of DNA, of molecular weight ranging from 12000 to 130000, and isoelectric points from pH 4.0 to 7.8.