锌(Ⅱ)没食子酸的配位行为及其与DNA的相互作用

Study on the Complexes of Gallic acid-Zn(Ⅱ) and the Interaction with DNA

用紫外光谱,荧光光谱以及高效液相色谱法,研究了没食子酸(GA)、Zn2+在接近生理条件下的配位行为及其与DNA的作用.探讨了溶液的pH值对配位行为的影响.计算了GA和Zn2+在溶液中的配位数,推测了二元配合物与DNA的作用方式,以及DNA对GA Zn2+体系的荧光淬灭常数.结果表明GA单独存在时,几乎不与DNA发生作用.当GA与Zn2+按1∶1形成配合物后,可以与DNA发生作用,三元复合物的形成,使体系的吸收光谱红移,荧光强度降低,HPLC的保留时间改变.GA在Zn2+介导下与DNA发生了较强的相互作用.

The interaction of gallic acid-Zn(Ⅱ) complex with DNA in solution was studied. The result showed that DNA could bind to calf thymus DNA in the presence of Zn ions, which have been confirmed by absorption, fluorescence spectra and HPLC. The increase of peak intensity and red shift of gallic acid in the presence of Zn^(2+) showed that GA-Zn^(2+) binary complex was formed. Much more spectra data showed that ternary complex of GA-Zn^(2+)-DNA was formed, through quenching the fluorescence of GA-Zn^(2+), (using) Stern Volmer equation to calculate the quenching constant Kq, and the style of quenching. The results of HPLC also showed the existing of complexes, by comparing the different of retention time among that of GA, DNA, GA-Zn^(2+) and GA-Zn^(2+)-DNA. The complex number is calculated, by the method of Asmus iso-absorbency. Furthermore, the form of complexes also could be affected by the pH value of the solution.