荧光光谱法研究除草醚与牛血清白蛋白的相互作用

运用荧光光谱和紫外吸收光谱研究水溶液中除草醚(NP)与牛血清白蛋白(BSA)的相互作用.结果表明,NP与BSA形成基态复合物导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移.运用位点模型计算298 K、308 K、318 K时结合常数K_A分别为6.97×10~4、5.25×10~4 、4.96×10~4 L·mol~(-1),结合位点数n分别为0.98、0.92、0.96.根据热力学参数确定其作用力以疏水作用和静电作用为主;运用F(o)rster偶极-偶极非辐射能量转移原理,测定了NP与BSA的结合距离r为2.19 nm;用同步荧光技术初步考察了NP对BSA构象的影响.

Study on the Interaction between Nithophen and Bovine Serum Albumin by Fluorescence Spectrometry

The interaction between nithophen (NP) and bovine serum albumin (BSA) in aqueous solution(Tris-HCl buffer, pH=7.4)was studied by fluorescence spectrometry and UV/Vis spectroscopy. The results showed that the fluorescence quenching of BSA by nithophen was a result of the formation of nithophen-BSA complex, and both static quenching and non-radioactive energy transferring occurred in the fluorescence quenching. The binding constants K_A at 298 K,308 K and 318 K were 6.97×10~4, 5.25×10~4 and 4.96×10~4 L·mol~(-1), respectively. And the number of binding sites n were 0.98,0.92 and 0.96,respectively. Based on the thermodynamic parameter analysis, the hydrophobic and electrostatic interaction between NP and BSA was confirmed to be the main binding force. The binding distance r(r=2.19 nm) between nithophen and BSA was obtained according to the F(o)rster theory of non-radioactive energy. Meanwhile, the effect of NP on the conformation of BSA was investigated using synchronous fluorescence spectrometry. The related interaction mechanism was preliminarily proposed.7