导数紫外光谱法研究牛血清白蛋白与十二烷基硫酸钠的相互作用

利用导数紫外光谱法研究了在pH=7.40,离子强度I=0.013 1 mo.lL-1的磷酸盐缓冲溶液中,浓度为1.5×10-5mo.lL-1的牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的过程中,芳香族氨基酸残基微环境极性的变化.通过研究发现,当SDS浓度小于5×10-4mol.L-1时,三种芳香族氨基酸残基微环境的极性几乎没有发生变化.当SDS浓度大于5×10-4mol.L-1时,苯丙氨酸(Phe)残基所处微环境的极性稍有增强,而酪氨酸(Tyr)残基所处微环境的极性在增强后稍有减弱,色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变.根据这些氨基酸残基所处微环境的极性的变化,可以判断BSA构象的变化.

The Interaction of Bovine Serum Albumin with Sodium Dodecyl Sulfate by Ultraviolet Second-Derivative Spectroscopy

The variation of the micro-environmental polarity of aromatic amino acid residues in the process of the interaction of bovine serum albumin（BSA）with sodium dodecyl sulfate（SDS）under the experimental conditions of phosphate buffer at pH 7.4,maintaining the ionic strength of the overall solution at I=0.013 1 mol.L-1 and the concentration of BSA at 1.5×10-5 mol.L-1,have been studied by ultraviolet second-derivative spectroscopy.The results showed that the micro-environmental polarity of the three aromatic amino acid residues varied hardly when the concentration of SDS below 5×10-4 mol.L-1.Upon slowly increasing the concentration of SDS beyond 5×10-4mo.l L-1,the micro-environmental polarity of phenylalanine residues showed a very slight increase in overall,and the tyrosine residues decreased a little after a slowly increasing,and the tryptophan residues varied hardly after a slowly decreasing.The changes of the conformation of BSA could been determined according to the variation of the micro-environmental polarity of these amino acid residues.