山奈酚抑制蛋白激酶CK2活性

研究体外以及HL-60细胞内山奈酚对蛋白激酶CK2的抑制作用及机制. 通过测定药物作用后转移到CK2底物上的[γ-32P]ATP的32P的放射性活度, 探讨山奈酚对重组人CK2全酶以及细胞内CK2活性的影响; 采用多重RT-PCR检测CK2α、α' 和 β亚基的mRNA表达水平; 通过 Lineweaver-Burk作图法,分析CK2的酶动力学机制.山奈酚能显著抑制重组人CK2活性（IC50 = 1.88 μmol/L）和HL-60细胞内的CK2活性, 对细胞内CK2的作用效果强于阳性对照四溴-2-氮杂苯并咪唑(TBB). 山奈酚作用2h,对CK2各亚基的mRNA表达水平均没有影响. 山奈酚对重组人CK2的酶动力学分析表明, 山奈酚与ATP(Ki = 1.14 μmol/L)及酪蛋白(Ki = 1.03 μmol/L)均呈非竞争性抑制作用. 结果提示, 山奈酚是一种有效的蛋白激酶CK2的抑制剂, 其作用机制可能与其阻碍CK2与ATP以及底物的结合有关.

Inhibitory Effect of Kaempferol on Protein Kinase CK2 in vitro and in HL-60 Cell

To investigate the inhibitory effects of kaempferol on protein kinase CK2 in vitro and in HL-60 cells. The effect of recombinant human CK2 holoenzyme activity and cellular CK2 activity by kaempferol was assayed by detecting incorporation of [γ-32P]ATP into the substrate. The mRNA expression of CK2α, α' and β subunits were detected by multiplex RT-PCR. CK2 kinetic analysis was carried out by using the Lineweaver-Burk plot. Kaempferol was shown to inhibit strongly the activity of protein kinase CK2 in vitro (IC50 =1.88 μmol/L) and in HL-60 cells. Intracellular CK2 activity assay showed that kaempferol was more effective than the positive control 4Br-2-azabenzimidazole (TBB). In addition, CK2α, α' and β mRNA level was not changed fundamentally during treatment for 2hours with kaempferol. Kinetic studies of kaempferol on recombinant human CK2 showed that the inhibition was noncompetitive with ATP (Ki = 1.14 μmol/L) and casein (Ki = 1.03 μmol/L). These results indicated that kaempferol was an effective inhibitor of protein kinase CK2, which is assumed to interfere the combination of CK2 and ATP or its substrates.