摘要
采用荧光光谱、三维荧光光谱、同步荧光光谱和紫外吸收光谱法,研究了不同温度下头孢呋辛酯(CFA)的浓度在1.959×10-6至13.71×10-6mol·L-1范围内,牛血清白蛋白(BSA)的浓度为2.0×10-6mol·L-1时两者之间的相互作用,按照Sterm-Volmer方程、Lineweaver-Burk方程和热力学方程分析和处理实验数据,计算了表观作用常数(KLB:3.907×106L·mol-1),热力学参数的平均值(焓变ΔH:-13.43kJ·mol-1,熵变ΔS:81.90J·K-1和标准吉布斯自由能变化ΔGθ:-38.34kJ·mol-1),测定了作用位点数(n:1.042),讨论了CFA对BSA的荧光猝灭作用机理。BSA和CFA作用可能形成了一种新的复合物,猝灭作用主要属于静态猝灭。认可热力学参数ΔH≈0,ΔS>0和ΔGθ<0,反应力主要是熵驱动力和静电作用力。在同步荧光光谱中色氨酸和酪氨酸的峰波长明显红移;在三维荧光光谱中,在加入CFA后二峰的发射波长蓝移;在紫外-可见吸收光谱图中,三体系的最大吸收明显不同,这些均显现色氨酸和酪氨酸所处的微环境的变化,同时说明了加入CFA后BSA的构象发生了变化。这为讨论BSA的构象变化,阐明CFA的药理作用和在生物体内的生物学效应等提供重要信息。
Under different temperatures and physiological conditions, with cefuroxime axetil concentrations in the range of 1.959×10^-6 to 13.71×10^-6 mol·L^-1, and bovine serum albumin （BSA） concentrations at 2.0×10^-6 mol·L^-1, the interaction between cefuroxime axetil and BSA was studied by fluorescence spectroscopy, three-dimensional fluorescence spectrum, synchronous fluorescence spectrum and UV-Vis absorption spectroscopy. After analyzing and processing the fluorescence quenching data at different temperatures according to Sterm-Volmer equation, Lineweaver-Burk equation and thermodynamic equation, the average value of the apparent binding constant （KLB： 3.907×10^6 L·mol^-1）, and thermodynamics parameters （enthalpy change △H： -13.43 kJ·mol^-1, entropy change △S： 81.90 J·K^-1 and standard Gibbs free energy change △G^θ： -38.34 kJ· mol^-1）were calculated, and the amounts of binding sites（n： 1.042）were measured. The fluorescence quenching mechanism of BSA after cefuroxime axetil was added was discussed. BSA was bound with cefuroxime axetil and formed a new compound. The quenching belonged to static fluorescence quenching. The thermodynamic parameters agree with △H≈0, △S〉0 and △G^θ〈0, and the binding reaction is mainly entropy-driven and electro-static interaction force plays a major role in the reaction. The maximum emission wavelength of Tyr and Trp had an obvious red shift in the synchronous fluorescence spectra, the fluorescence emission wavelength of two peaks had a blue shift in the three-dimensional fluorescence spectrum of BSA in the presence of cefuroxime axetil and the maximum absorbtion wavelenghs of three systems in the UV-Vis absorption spectra were obviously different. These showed that the changes in the micro-environment of Tyr and Trp and demonstrated that the conformation of BSA changed as cefuroxime axetil had been added. This provides important information for discussing the configuration modification of BSA because of the added cefuroxime axetil, and for elucidating the pharmacological effects of cefuroxi me axetil and biological effects in the organism.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2008年第9期2139-2143,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(30570015,20373051)
湖北省自然科学基金项目(2005ABA067)资助
关键词
头孢呋辛酯
牛血清白蛋白
荧光猝灭光谱
三维荧光光谱
热力学参数
Cefuroxime axetil
Bovine serum albumin
Fluorescence spectrum
Three dimensional fluorescence spectrum
Thermodynamic parameters
