槲皮素-7,4′-二硫酸酯钠对重组人CK2全酶的抑制作用及动力学分析

目的观察槲皮素-7,4′-二硫酸酯钠(sodium quercetin-7,4′-disulphate,SQDS)对重组人CK2全酶的直接作用及酶动力学机制。方法通过测定转移到CK2底物上的［γ-³²P］ATP的³²P放射活度检测不同条件下的重组人CK2全酶的活性。结果重组人CK2是一种Ca²⁺,cAMP和cGMP等第二信使非依赖性蛋白激酶,与天然CK2的性质一致。SQDS对重组人CK2全酶有很强的抑制作用,IC₅₀为4.4 μmol·L^-1,抑制作用大于已知CK2抑制剂DRB和A3。CK2的动力学研究表明:SQDS与ATP和酪蛋白分别呈竞争性和非竞争性抑制作用。结论SQDS是有效的CK2抑制剂,对于开发更有效的CK2抑制剂及将SQDS用于临床提供了一定的实验依据。

Inhibitory effect and kinetic analysis of sodium quercetin-7,4''-disulphate on recombinant human protein kinase CK2 holoenzyme]

AIM: To study the direct effect and kinetics of sodium quercetin-7,4'-disulphate (SQDS) on recombinant human protein kinase CK2 holoenzyme. METHODS: The recombinant human CK2 holoenzyme activity was assayed by detecting incorporation of 32P of [gamma-32P] ATP into the substrate in various conditions. RESULTS: The recombinant human CK2 was a second messenger (Ca2+, cAMP and cGMP) independent protein kinase. The characterization and function of the reconstituted holoenzyme were consistent with those of native CK2. SQDS was shown to strongly inhibit the holoenzyme activity of recombinant human protein kinase CK2 with an IC50 of 4.4 mumol.L-1, which was more effective than DRB and A3, known CK2 special inhibitors. Kinetic studies of SQDS on recombinant human CK2 showed: the inhibition was competitive with ATP and noncompetitive with casein. CONCLUSION: SQDS is a potent inhibitor of protein kinase CK2. This study provide experimental basis for the development of more effective inhibitors of CK2 and for clinical application of SQDS in the future.