Panel A: Whole cell extracts prepared by using our protocol (lanes 1, 4, 7 and 10), prepared according to Healy’s protocol (lanes 2, 5, 8 and 11), and acid histones extracts (lanes 3, 6, 9 and 12) from Jurkat cells were resolved using 4–12% Bis-Tris gels and probed with streptavidin (SA). Protein identities were verified by using antibodies to PC, histone H3, and histone H4. Panel B: As described for panel B, but HeLa cells were substituted for Jurkat cells. Lanes loaded with acid extracts were electronically combined with those loaded with whole cell extracts.