等温滴定量热法研究牛血清白蛋白与十二烷基二羟乙基甲基溴化铵的相互作用

Isothermal titration calorimetric study on interactions between bovine serum albumin and N-dodecyl-di(2-hydroxyehtyl)-methyl ammonium bromide

用等温滴定热量计测定了牛血清白蛋白(BSA)与十二烷基二羟乙基甲基溴化铵(DDHAB)的相互作用焓,探讨了表面活性剂浓度、温度和盐浓度等对相互作用焓的影响.BSA与表面活性剂相互作用焓是静电作用、去水化作用、疏水作用和表面活性剂胶束化等协同作用的结果,在其他条件保持不变时,相互作用焓随表面活性剂浓度改变,在临界胶束浓度(CMC)前后区域分别出现吸热峰.加入NaCl可引起相互作用焓峰值及其位置的变化.

Interaction enthalpies between bovine serum albumin（BSA） and N-dodecyl-di（2-hydroxyehtyl）-methyl ammonium bromide（DDHAB） have been determined in an isothermal titration calorimeter.The influences of temperature,concentrations of surfactant and the added salt in the solutions on the interaction enthalpy have been discussed.The interaction enthalpies between BSA and a surfactant are resulted from the cooperative effects of electrostatic interaction,dehydration,hydrophobic interaction and surfactant micellization.The interaction enthalpy changes against the surfactant concentration with two endothermic peaks observed in the regions before and after the critical micelle concentration（CMC）.The addition of NaCl in the surfactant solution can lead to the value change of the interaction enthalpy and the position change of the endothermic peaks.