5种荧光染料探针与牛血清白蛋白相互作用研究

采用荧光光谱法研究了水溶液中四溴荧光素、四氯四溴荧光素、二碘荧光素、乙基罗丹明B、健那绿B等5种荧光染料探针与牛血清白蛋白(BSA)的相互作用.实验表明,这5种染料探针同牛血清白蛋白结合时,疏水作用力起决定性作用,静电力起次要作用,相比之下牛血清白蛋白(BSA)结合阴离子的能力最强,其次为中性分子,最后为阳离子.通过疏水作用力,5种染料均是以非极性苯基进入BSA疏水性腔体中同色氨酸残基发生作用,弱氢键的形成加强了这种作用力,且使得光谱间能量转移效率明显提高.5种染料探针的极性部位由于极性和空间效应的原因难以进入腔体内部,致使反应均按接近1∶1的方式进行.

Study on the interaction between spectral probes and bovine serum albumin

The binding reaction between Tetrabromofluorescein,Tetrachloro-tetrabromofluorescein,diiodofluorescein,Ethylrhodamine B,Janus green B with bovine serum albumin(BSA) in aqueous solution was studied by fluorescence and ultraviolet-visible absorption spectra.The results show that hydrophobic force plays the decisive role and electrostatic force on the secondary role in the reactions.In contrast,bovine serum albumin can most firmly combine with anions,secondly with neutral molecules,finally for the cations.The fluorescent probes insert their common nonpolar phenyl into hydrophobic cavity of BSA through hydrophobic force where they finally combine to tryptophanyl and the formation of weak hydrogen bonds strengthen the action and makes energy transfer efficiency improved significantly.Because of the polar and spacial effects their polar parts can not enter to the cavity,so the reactions all take place by nearly 1∶1 manner.