In a series of pull-down experiments from the lysates of HeLa cells, the effects of 0.1, 0.5, 1, 2, 5, 10, 25, and 50% loadings of PK inhibitors is determined. Examine higher bead loadings (75 and 100%) are prevented due to lack of compound solubility and poor reproducibility of the synthesis outcomes. 50% loading is the highest feasible in this study[1].