烟酰胺与DNA相互作用的电化学研究

Electrochemical Investigation on the Interaction between Nicotinamide and DNA

利用示差脉冲伏安法研究了烟酰胺(NA)与小牛胸腺DNA在pH8.0条件下相互作用的电化学行为。双链DNA(dsDNA)或单链DNA(ssDNA)的存在导致NA的峰电流明显降低且峰电位负移,表明NA与DNA发生相互作用,生成了复合物,且其作用模式主要是静电模式,但NA与dsDNA的相互作用强于与ssDNA的相互作用,可用于识别dsDNA和ssDNA。通过dsDNA加入前后峰电流的变化,计算得出NA与dsDNA结合常数β=4.946×1011,结合位点数m=3。此外,NA的峰电流IP与DNA质量浓度在1～14mg/L的范围内呈线性关系,线性回归方程为IP(10-5A)=-0.03451cDNA(mg/L)+1.7408,相关系数R为0.9998。该法具有良好的回收率和选择性,可用于样品中DNA的测定。

The electrochemical behavior of the interaction of nicotinamide （NA） and DNA at pH 8.0 was investigated by differential pulse voltammetry. After the addition of the dsDNA or ssDNA, the peak currents declined with the peak potential of NA shifting negatively. The results showed that a complex was formed due to the interaction of NA and DNA, and electrostatic attraction existed between NA and dsDNA or ssDNA. The interaction between NA and dsDNA was more strongly than that with ssDNA, by which dsDNA and ssDNA could be distinguished. The binding site m and the binding constant fl of NA to DNA were 3 and 4.946 × 10^11, respectively. The peak current showed a linear relationship with the DNA concentration in the range of 1 - 14mg/L, and the linear regression equation was Ip （10^-5A） = - 0.03451 C DNA （mg/L） ＋ 1.7408 with the correlation coefficient of 0.9998. This method exhibits a good recovery and selectivity, which could be applied to the determination of DNA in sample.