荧光光谱法研究共存物对白杨素与BSA相互作用的影响

Effect of Coexisting Substances on the Interaction between Bovine Serum Albumin and Chrysin Investigated by Fluorescence Spectroscopy

运用荧光光谱法研究了共存物亚硝酸钠、葡萄糖或维生素C对白杨素（CHR）与牛血清白蛋白（BSA）相互作用的影响。结果表明：无共存物时，白杨素对BSA的荧光猝灭过程为静态猝灭，结合常数K值为10^3～10^4数量级，结合位点数n近似等于1，分子间相互作用力以疏水作用力为主；亚硝酸钠、葡萄糖、维生素C分别参与下，白杨素对BSA的荧光猝灭类型由静态猝灭转变为动态猝灭，葡萄糖的参与使白杨素与BSA之间作用力类型由疏水作用力转为氢键与范德华力，亚硝酸钠或维生素C的分别存在不影响白杨素与BSA的作用力类型；三种外加试剂的单独参与均使得白杨素与BSA的结合常数明显增大，结合位点数略有增加，但仍维持在1左右。初步探讨了共存物影响白杨素与BSA结合的可能方式。

The effect of coexisting substances （NaNO2, glucose or vitamin C） on the interaction between bovine serum albumin （BSA） and chrysin （CHR） was investigated by UV-Vis and fluorescence spectroscopy. Results obtained from fluorescence spectra indicated that CHR had a strong ability to quench the intrinsic fluorescence of BSA through a static quenching procedure in the absence of coexisting substances. The magnitude of the binding constant K in CHR-BSA system was about 10^3- 10^4 and the number of binding sites of chrysin on BSA was about 1. The major driving force in CHR- BSA system was hydrophobic force. But in the present of NaNO2, glucose or vitamin C, the quenching type of BSA intrinsic fluorescence by CHR was changed from static quenching to dynamic quenching. The main driving force in CHR-BSA binding process was changed from hydrophobic force to hydrogen bond formation and van der Waals forces in the present of glucose. Whereas, the type of main driving force of CHR-BSA system unchanged in the presence of NaNO2 or vitamin C. The value of the binding constant K in CHR-BSA binding process was increased evidently in the present of each coexisting substance at different temperatures. The number of binding sites of CHR on BSA was still about 1. The mechanism of coexisting substance interference on the interaction between BSA and CHR was discussed.