N-十六烷基-羟乙基-二甲基溴化铵与牛血清白蛋白的结合作用

Interactions between N-Cetyl-Hydroxyethyl-Dimethyl Ammonium Bromide and Bovine Serum Albumin

用荧光光谱法研究了298K时Tris-HC l缓冲溶液(pH=7.1)中季铵盐类表面活性剂N-十六烷基-羟乙基-二甲溴化铵(CHDAB)与牛血清白蛋白(BSA)的结合作用.考察了BSA浓度对结合作用的影响,用Stern-Volmer方程探讨了CHDAB在浓度较低区域与BSA的作用机制,用位点结合模型计算了CHDAB与BSA结合反应的结合常数KA和结合位点数n,用同步荧光技术考察了CHDAB对BSA构象的影响.结果表明:CHDAB对BSA的内源荧光有猝灭作用,并导致其最大发射波长蓝移;相同温度下,BSA浓度越小,其Stern-Volmer猝灭常数Ksv越大,CHDAB对BSA的猝灭作用越强,同时其结合常数也越大,结合越强;同步荧光光谱表明CHDAB对BSA构象产生了一定影响.

Interactions between N-cetyl-hydroxyethyl-dimethyl ammonium bromide（CHDAB）and bovine serum albumin（BSA）in Tris-HCl buffer solution（pH=7.1）were studied by fluorescence spectroscopy at 298 K.Effects of BSA concentration on the interactions were examined.The interaction mechanism between BSA and CHDAB at a relatively low concentration range was discussed using the Stern-Volmer equation.The binding constant KA and the number of binding site n of the interaction between CHDAB and BSA were calculated using site binding mode.The addition of CHDAB on the conformation of BSA was analyzed using synchronous fluorescence spectrometry.Results showed that CHDAB has a fluorescence quenching effect on BSA and leads to a blue shift of the maximum emission wavelength.At the same temperature,both the Stern-Volmer quenching constant and the binding constant increase with decreasing concentration of BSA,which indicates that stronger binding and fluorescence quenching are observed at lower concentration of BSA.The measurements of synchronous fluorescence spectrometry on tyrosine residues and tryptophan residues also show that the existence of CHDAB has an effect on the conformation of BSA.