Cleavage of procaspase-3 in Raji cells. Daudi and Raji cells were stimulated with 500 μmol/L t-BHP for the indicated periods, and then cell lysates were prepared. Samples were loaded onto 13% SDS-PAGE gels. Transferred proteins on polyvinylidene difluoride (PVDF) membranes were reacted with polyclonal rabbit anti–caspase-3 antibody (PharMingen). This experiment was repeated 3 times with similar results.