Inhibitory effect of quercetin on recombinant human protein kinase CK2 holoenzyme and its kinetics analysis / 中草药

ABSTRACT

Object To study the direct effect of quercetin on recombinant human protein kinase CK2 holoenzyme and its kinetics. Methods Recombinant human protein kinase CK2? and ? subunits were cloned and expressed by gene engineering, and were purified. The two subunits were mixed at the same molar ratio, thus reconstituting CK2 holoenzyme, which displayed the maximum bioactivity. The CK2 activity was assayed by detecting incorporation of 32 P of [? 32 P] ATP into the substrate in the various conditions. Results The recombinant human protein kinase CK2 was the second messenger (Ca 2+ , cAMP and cGMP) independent protein kinase, the characterization and function of the reconstituted holoenzyme were consistent with those of native CK2. It was found that quercetin strongly inhibited the holoenzyme activity of recombinant human protein kinase CK2 with an IC 50 of 522 nmol/L, which was much more effective than DRB and A3, known as CK2 special inhibitors. Kinetic studies of quercetin on recombinant human protein kinase CK2 showed the inhibition was competitive with ATP and noncompetitive with casein. Conclusion Quercetin is a potent inhibitor of recombinant human protein kinase CK2. The inhibition may be another molecular mechanism of antitumor effect of quercetin. This study provides a simple and rapid screening method for the development of more effective inhibitors of recombinant human protein kinase CK2.