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利用紫外吸收光谱、荧光光谱、圆二色光谱(CD)和琼脂糖凝胶电泳等手段研究了八羟基喹啉铜(Ⅱ)配合物Cu[8-OHQ]2与DNA和蛋白质的相互作用.实验结果表明,在生理条件下,Cu[8-OHQ]2能通过插入方式较强的与CT-DNA结合,诱导DNA构象的改变.其本征结合常数Kb为1.15(±0.01)×105 L/mol,表观结合常数Kapp为4.21×106 L/mol.再者,琼脂糖凝胶电泳实验表明,在生理条件和抗坏血酸(Vc)存在情况下,Cu[8-OHQ]2能有效地将超螺旋pBR322质粒DNA切割成缺刻和线性,甚至降解为小的片断.机理研究表明扩散的·OH,H2O2和1 O2都不是在切割过程中起作用的活性氧物种(ROS);copper-oxo中间体可能是此切割过程中主要的活性氧物种.另外,Cu[8-OHQ]2也能以适中的结合力与牛血清白蛋白(BSA)结合而猝灭BSA内源荧光,猝灭机理为静态猝灭.所有这些结果表明Cu[8-OHQ]2具有作为潜在化疗试剂的生物活性.
The interaction between Cu (8-OHQ) 2 and Cu (8-OHQ) 2, a complex of copper (Ⅱ) octahydroxyquinoline, was studied by UV absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy (CD) and agarose gel electrophoresis. The experimental results show that under physiological conditions, Cu [8-OHQ] 2 can induce DNA conformational change by binding strongly to CT-DNA with an intrinsic binding constant Kb of 1.15 (± 0.01) × 105 L / mol and the apparent binding constant Kapp was 4.21 × 106 L / mol. In addition, agarose gel electrophoresis showed that Cu [8-OHQ] 2 could effectively immobilize The supercoiled pBR322 plasmid DNA was cut into nicks and linear, and even degraded into small fragments.Mechanism studies showed that diffusion of · OH, H2O2 and 1 O2 were not reactive oxygen species (ROS) during the cleavage process; intermediate of copper-oxo In addition, Cu [8-OHQ] 2 can also quench the endogenous fluorescence of BSA with moderate binding affinity to bovine serum albumin (BSA). The quenching mechanism is Static quenching All of these results indicate that Cu [8-OHQ] 2 has biological activity as a potential chemotherapeutic agent.