title: [Study of heterogeneity of chromatin endonuclease fragments, using fractionation by step-wise endonucleolysis].
abstract: Isolated nuclei from rat liver were incubated at different time intervals under conditions, optimal for manifestation of the Ca, Mg-dependent endonuclease activity. After each of the 6 endonucleolyses chromatin was extracted and 6 chromatin fractions (I--VI) and "residual" chromatin were collected.  A comparative analysis of the "early" (I--III) and "late" chromatin fractions revealed an increased RNA content in the "late" fractions and changes in the composition of the non-histone proteins. Electrophoresis in acrylamide gel concentration gradient demonstrated that fractions I--III predominantly contain high molecular weight fragments whereas fractions IV-VI are represented by highly fragmented chromatin. Each fraction was characterized by peculiar shapes of alkaline denaturation curves and by heterogeneity of charges of their constituent chromatin fragments.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002467:Cell Nucleus / Q000201:enzymology; D002843:Chromatin / Q000032:analysis / Q000201:enzymology*; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis; D003851:Deoxyribonucleases / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D004789:Enzyme Activation; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D012313:RNA / Q000032:analysis; D051381:Rats
chemical_list: D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D012313:RNA; D003851:Deoxyribonucleases; D004720:Endonucleases; D008274:Magnesium; D002118:Calcium
vernacular_title: Issledovanie geterogennosti endonukleaznykh fragmentov khromatina. Fraktsionirovanie metodom stupenchatogo endonukleoliza.