1-十四烷基-3-甲基咪唑溴与BSA相互作用研究

Study of interactions between 1-tetradecyl-3-methylimidazolium bromide and bovine serum albumin

研究牛血清白蛋白(Bovine Serum Albumin,BSA)与咪唑型表面活性剂的相互作用,可以补充咪唑型表面活性剂的基础数据,拓宽其应用范围。选取1-十四烷基-3-甲基咪唑溴/BSA(C_(14)mimBr/BSA)体系,使用表面张力仪、电导率仪、远紫外圆二色光谱仪、荧光光谱仪及等温滴定微量热仪,考察了C_(14)mimBr与BSA的相互作用。结果表明:低浓度的C_(14)mimBr与BSA以静电相互作用结合,稳定了BSA的二级结构;高浓度的C_(14)mimBr与BSA以疏水相互作用结合,破坏了BSA的二级结构并最终导致其变性。C_(14)mimBr与BSA内部空腔的色氨酸残基的主要作用方式为疏水相互作用,每克BSA可以结合约为2×10^(-4)mol的C_(14)mimBr,不同温度下结合量略有差别。C_(14)mimBr无论是在保护还是破坏BSA结构方面的能力都要优于传统的阳离子表面活性剂十四烷基三甲基溴化铵(TTAB)。

Studying interaction between bovine serum albumin(BSA)and imidazole surfactant can supplement the basic data of the surfactant and expand its potential applications.The system of 1-tetradecyl-3-methylimidazolium bromide/BSA(C_(14)mimBr/BSA)was selected,and the interaction between C_(14)mimBr and BSA was investigated by various analytical techniques,including surface tensimeter,conductivity meter,far ultraviolet circular dichroism spectrometer,fluorescence spectrometer and isothermal titration microcalorimeter.The results show that at lower concentrations of C_(14)mimBr,electrostatic interactions dominate,with the addition of C_(14)mimBr serving to stabilize the secondary structure of BSA.Conversely,at higher concentrations of C_(14)mimBr,hydrophobic interactions become prominent,causing the disruption of BSA's secondary structure and eventual denaturation.The interaction between C_(14)mimBr and the tryptophan residue within BSA's internal cavity primarily involves hydrophobic interactions.The binding capacity of C_(14)mimBr to BSA is about 2×10^(-4)mol per gram with minimal variation across different temperatures.It can be seen that C_(14)mimBr is superior to tetradecyl trimethyl ammonium bromide(TTAB)in both protecting and destroying BSA's structure.