CBP-501 acetate, a cell-permeable calmodulin-binding peptide and a G2-abrogating drug candidate, inhibits the activity of multiple Ser216-specific kinases, such as MAPKAP-K2, C-Tak1, CHK1 and CHK2, with IC50 values of 0.9 μM, 1.4 μM 3.4 μM and 6.5 μM, respectively. CBP-501 acetate is used for various types of cancer[1][2].