title: Polylysine titration of rat liver chromatin fractions after DNase II digestion.
abstract: The concentration of free phosphate groups is measured in rat liver chromatin after DNase II digestion using polylysine titration. The unsheared chromatin completely precipitates at lysine/DNA phosphate ratios of 0.5 to 0.6. Digestion of the chromatin reduces the lysine/DNA phosphate ratio of complete precipitation by about 0.2 units suggesting  the removal of free phosphate groups. The two chromatin fractions: MgC12 insoluble (template-inactive) and Mg12 soluble (template-active) chromatins precipitate at about the same lysine/DNA phosphate ratio. Some 15% of the MgC12 soluble chromatin remains in solution at any polylysine concentration. The removal of histone H 1 FROM THE MgC12 insoluble chromatin increases the lysine/DNA phosphate ratio by about 0.2 units suggesting that 20% of the DNA phosphate groups in nucleosomes are masked by histone H 1.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002843:Chromatin / Q000032:analysis*; D004247:DNA / Q000032:analysis*; D003851:Deoxyribonucleases; D008099:Liver / Q000032:analysis*; D008274:Magnesium; D009943:Organophosphorus Compounds / Q000032:analysis; D011107:Polylysine; D051381:Rats; D012995:Solubility; D013698:Templates, Genetic; D013950:Thymus Gland
chemical_list: D002843:Chromatin; D009943:Organophosphorus Compounds; D011107:Polylysine; D004247:DNA; D003851:Deoxyribonucleases; D008274:Magnesium