Catabolism of nuclear proteins in control and phytohemagglutinin-stimulated human lymphocytes, leukemic leukocytes, and Burkitt lymphoma cells.

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of nuclear non-histone proteins extracted with 0.15 and 0.30 M NaCl from human normal lymphocytes or leukemic leukocytes indicated a lack of bands in the highermolecular-weight regions of the gels. However, the corre sponding fractions from phytohemagglutinin-stimulated lymphocytes and Burkitt lymphoma cells did contain highmolecular-weight protein bands. Moreover, high-molecu lar-weight bands were present in the non-histone protein fraction extracted with 1% SDS:4 M urea ("tightly bound"