Western blot detection of Chk2 phosphorylation using nocodazole-treated HeLa cells. Blots were probed with Chk2 (B-4): sc-17748 (A) and p-Chk2 (Thr 68)-R: sc-16297-R (B, C). In B and C, the antibody was preincubated with cognate phosphorylated or unphosphorylated peptide, respectively.