Binding of benzo(a)pyrene into lung and thymocyte nuclear fractions

Binding of (3H)benzo(a)pyrene into lung and thymocyte nuclear fractions is studied in short term cultures. DNA, RNA and protein in the subnuclear fractions is separated and tightly bound radioactivity is measured. Among the fractions, proteins of the matrix sediment fraction display the highest specific radioactivity. DNA has a low specific radioactivity as compared to that of RNA and protein in all fractions. In thymocyte matrix extract and chromatin fractions the specific radioactivity of RNA exceeds that of protein. Lung nonhistones display a 30 times higher specific radioactivity as compared to histones. The corresponding ratio of the thymocyte fractions is about 10.