山梨酸钾与蛋白质相互作用的荧光和共振光散射光谱研究

Interaction between Potassium Sorbate and Bovine Serum Albumin Revealed by Fluorescence and Resonance Light Scattering Spectra

用荧光光谱和共振散射光谱(RLS)对山梨酸钾(PSA)与牛血清蛋白(BSA)在溶液中的相互作用进行了研究,探讨了PSA对BSA荧光和共振光散射猝灭的机理,测定了该反应的表观结合常数及结合位点数。在288和293 K时的表观结合常数分别为2.23×103和2.74×103L.mol-1,其相应的结合位点数分别为1.02和0.99。利用热力学参数确定了分子间的作用力性质,作用过程是自发的,作用力主要是电子作用力。同步荧光光谱表明相互作用对蛋白质构象有一定的影响。基于Forster非辐射能量转移理论估算了山梨酸钾与蛋白质之间的结合距离。

The interaction between potassium sorbate （PSA） and bovine serum albumin （BSA） was investigated by fluorescence spectroscopy, resonance light-scattering （RLS） spectroscopy. The quenching mechanism was analyzed referring to PSA against the fluorescence and the resonance light scattering spectra of BSA. The apparent binding constants （KA ） between PSA and BSA were 2.23 ×10^3 L·mol^-1 （288 K）, and 2. 74×10^3 L.mol^-1 （293 K） , respectively. The corresponding binding sites values （n） were 1.02 and O. 99. The changes of negative entropy change and enthalpy indicate that the interac- tion of PSA and BSA was driven mainly by electrostatic interactions. The binding process was a spontane- ous process in which Gibbs free energy change was negative. The effect of PSA on the conformation of BSA was analyzed by synchronous fluorescence spectroscopy. Furthermore, the binding distance r = 2. 83 nm between PSA and BSA was obtained based on the mechanism of Forster non-radiation energy transfer.