The solubility of calf thymus chromatin in sodium chloride

The solubility of calf thymus chromatin and chromatin depleted of F1-histone has been examined under various conditions in sodium chloride. F1-depleted DNH was more soluble than native DNH at low concentrations but this difference became small at high concentrations (1mg/ml). Both exhibited minimum solubility in 0.15M -NaCl. The effect of pH and of maleylation of the mino acid side chains on the solubility implied that electrostatic interactions dominated the precipitation reaction. Urea had no effect on the solubility of either complex. N.m.r. studies showed that the chromatin behaved as a rigid complex at all salt concentrations less than 0.6 molar.