荧光光谱法研究十六烷基三甲基溴化铵与牛血清白蛋白的相互作用

Fluorescence Spectra of Binding Reaction Between Cetyltrimethylammonium Bromide and Bovine Serum Albumin

在模拟体液条件下,用荧光光谱研究了在不同温度下十六烷基三甲基溴化铵(CTAB)与牛血清白蛋白(BSA)结合反应的光谱行为。结果发现,CTAB对BSA有较强的荧光猝灭作用。用Stern-Volmer和Lineweaver-Burk方程分别处理试验数据,发现BSA与CTAB发生反应生成了新的复合物,属于静态荧光猝灭。由Lineweaver-Burk方程求出了不同温度下反应时复合物的形成常数KA(305K,7.09×104L/mol;310K,4.97×104L/mol;及对应温度下结合反应的热力学参数(ΔH=-55.85kJ/mol;ΔS=-90.26J/(mol.K)/-90.55J/(mol.K);ΔG=-28.32(kJ/mol)/-27.87(kJ/mol),证明二者之间的主要作用力为氢键和范德华力。同步荧光光谱发现,CTAB使BSA色氨酸残基疏水性略有增强。

The interaction of cetyhrimethylammonium bromide （CTAB） with bovine serum albumin （BSA） was investigated by fluorescence spectroscopy and synchronous fluorescence under simulative physiological conditions. In the mechanism study, it shows that the fluorescence quenching of BSA by CTAB is static quenching 7.09 ×10^4 er with the formation of a complex of BSA and CTAB. The binding constant KA （305 K： L/mol; 310 K： 4.97×10^4 L/mol） and thermodynamic parameters（△H = -55.85 kJ/mol; AS = -90. 26 J/（mol · K）/- 90. 55 J/（mol · K） ; △G = - 28.32 （kJ/mol）/- 27.87 （kJ/mol） at different temperatures were calculated according to Lineweaver-Burk equation. The thermodynamic paramters show hydrogen bond and Van der Waals interactions play important roles to stabilize the complex. The result of synchronous fluorescence indicates that the polarity around the tryptophan residues has decreased and the hydrophobicity has increased.