Quantitative analysis of the distribution of 3H-leucine in acid soluble chromatin proteins of Noviknoff hepatoma cells separated by two-dimensional polyacrylamide gel electrophoresis.

The acid soluble proteins of Novikoff hepatoma chromatin were labeled linearly with 3H-leucine for 16 minutes. Analysis on two-dimensional polyacrylamide gels showed that 13 of the 18 stained proteins were detected by autoradiography after a 16-minute in vitro incubation. The labeled molecules include the histones H2A, H2B, H3, and H4; and proteins A3, Aj, A8, A8', A15, A16, A24, B7, and B13. Relatively large amounts of isotope were incorporated into two other proteins, A3 and Aj, in addition to the histones. Some proteins, notably Aj, A8, A8' and A16 were labeled to a greater extent than would be expected on the basis of uptake of Coomassie Brilliant Blue R. None of the labeling patterns were characteristic of a precursor-product relationship either the histones or the nonhistone proteins.