荧光光谱法研究甲基蓝与羊毛角蛋白的相互作用  

Study on the Interaction between Methyl Blue and α-Keratin by Fluorescence Spectroscopy

作　　者：田鹏[1] 李华[1] 赵春贵[1] 

机构地区：[1]山西大学生物技术研究所化学生物学与分子工程教育部重点实验室,山西太原030006

出　　处：《山西大学学报（自然科学版）》2009年第2期253-257,共5页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(30740038)

摘　　要：在0.1 mol/LTris-HCl弱酸和中性缓冲液中,采用荧光光谱法研究了甲基蓝(MB)与羊毛α-角蛋白相互作用.结果表明:在25℃和37℃,pH分别为5.45、6.25和7.20,MB与α-角蛋白结合形成1∶1配合物,猝灭蛋白质内源荧光,敏化MB峰位在460 nm处的荧光.它们之间的结合反应是吸热、熵增驱动的自发过程,即反应过程中△H>0和△S>0,则其主要作用力是疏水作用.中性pH时其结合常数增大,表明中性环境蛋白质的局部构象更有利于MB的疏水结合.同时,37℃与25℃结合常数相比,37℃环境的KA大于25℃,与反应过程是吸热过程即△H>0的结果一致.The interactions between methyl blue （MB） and a-keratin were studied by fluorescence spectra in 0.1 mol/L Tris-HCl weakly acidic and neutral buffer. The results indicated that coordination compound was formed at 25 ℃ and 37 ℃ in three pH ： 5.45,6.25 and 7.20. The intrinsic fluorescence of a-keratin was quenched by MB of which the peak was sensitized at 460 nm. Based on the thermodynamic parameters cal- culated,the entbalpy change AH and entropy change △S for the process of MB binding to a-keratin were greater than 0, indicating that the binding was mainly entropy-driven and the enthalpy was unfavorable. These results suggested that the hydrophobic forces plaied a major role in the reaction. The apparent bind- ing constant was increase at neutral pH condition, indicating that the part conformation of a-keratin was advantageous for hydrophobic combination in this situation. The binding constant of 37 ℃ was larger than 25 ℃. The result was consistent with endothermic process that △H was greater than 0.

关 键 词：甲基蓝 α-角蛋白 荧光光谱 

分 类 号：Q502[生物学—生物化学] Q629.73