Fractionation of rat-liver-chromatin nonhistone proteins into two groups with different metabolic rates.
In the pH interval 10.5-11.8, 70% of the nonhistone proteins normally present in rat liver chromatin were dissociated. The rest remained complexed with DNA even at pH 13. Dodecylsulfate-polyacrylamide gel electrophoresis revealed that the majority of the high-molecular-weight nonhistone proteins together with a few characteristic fractions with molecular weights of 40 000-60 000 remained in the alkali-resistant group. L-[14C]Leucine pulse-labelling experiments showed that the specific radioactivity of the alkali-labile nonhistone proteins was 2-3 times higher than that of the alkali-resistant nonhistone proteins, which, in turn, had the same specific radioactivity as that of the histones. The same held true for chromatin from regenerating rat liver. In the course of a 21-day chase the specific radioactivity of the alkali-labile nonhistone proteins gradually decreased and finally became 3 times lower than that of the alkali-resistant nonhistone proteins. On the contrary, the ratio of the specific radioactivities of the alkali-resistant nonhistone proteins and of the histones to the specific radioactivity of DNA remained constant during the chase. A conclusion can be drawn that a fraction of liver nonhistone proteins exists which is alkali-resistant and is conserved in chromatin like histones.
D000818:Animals; D002843:Chromatin / Q000032:analysis / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007930:Leucine / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D013936:Thymidine / Q000378:metabolism
D002843:Chromatin; D006657:Histones; D011506:Proteins; D004247:DNA; D007930:Leucine; D013936:Thymidine