Dose- dependent response, kinetics analysis and reversibility assay of CK2 inhibition by hematein. A. CK2 was assayed with specific peptide described in the material and method section with the increasing concentrations of the inhibitor using 10 μM and 100 μM ATP. B. The Linewear-Burk plots illustrate the non-competitive inhibition of hematein relative to ATP toward CK2. Substrate concentration was fixed at 200 μM. CK2 activity was determined in 0 μM, 1 μ and 4 μM hematein. The data represents means of duplicate experiments with SE never exceeding 10%. C. Reversibility assay of hematein. Hematein was pre-incubated with CK2 at a concentration of 5 μM for 30 minutes and then kinase assay was performed under 0.2 μM final concentration of hematein. Ck2 kinase activity is represented as relative CK2 activity to controls (DMSO). Data points represent the average of duplicate experiments and bars indicate SD. D. The Linewear-Burk plots illustrate the mixed inhibition of hematein relative to substrate toward CK2. ATP concentration was fixed at 10 μM. CK2 activity was determined in 0 μM, 1 μM and 4 μM hematein. The data represents means of duplicate experiments with SE never exceeding 10%.