Physicochemical properties of salt-soluble, unsheared chromatin. Molecular weight studies.

A chromatin fraction, which can reproducibly be extracted from rat liver nuclei at moderate salt concentration (0.1 M (NH4)2SO4, 0.1 M Tris-HCl, 2 mM MnCl2, pH 7.

Ionic strength dependent structural changes of nucleosomes.

Rat thymus nucleosomes were studied as to their sedimentation behaviour and molecular weight Mr in NaCl and (NH)2SO4 solutions of different ionic strengths. The sedimentation coefficient s20,w decreases in two steps at ionic strengths of about 0.45-0.