苯酚磺酞类酸性染料与牛血清白蛋白的结合反应

Reactions Between Acidic Phenolsulfonphthaleins and Serum Albumin

应用荧光光谱法研究了水溶液体系中,苯酚磺酞类酸性染料苯酚红、甲酚红、氯酚红、溴酚红、甲酚紫与牛血清白蛋白(BSA)之间的相互作用.实验表明:苯酚磺酞类酸性染料对牛血清白蛋白的荧光有较强的猝灭作用,其荧光猝灭主要为静态猝灭,从荧光猝灭结果中求得不同温度下各种染料与BSA的结合常数K,发现染料取代基的引入使K值增大,且随反应温度上升K值下降.由染料与BSA反应焓变、熵变,确定染料与BSA的结合主要是静电引力.依据非辐射能量转移机理,探讨了不同温度下该类染料与BSA相互结合时,其给体-受体间距离和能量转移效率,进一步证实了该类反应为单一静态猝灭过程,且阐明了其猝灭机理是通过能量转移产生的.

The reactions between BSA and acidic phenolsulfonphthaleins including phenol red, cresol red, chlorophenl red, bromocresol red and m-cresol purple have been investigated by means of fluorescence spectra. The experimental results showed that all of the selected acidic phenolsulfonphthaleins strongly quenched the fluorescence produced by BSA, and this fluorescence quenching could be interpreted in terms of static quenching. From the calculation results of binding constants K for these dyes at various temperatures, it could be found that the increase in the functional groups number of dyes molecules resulted in an increase in K, while the increase in reaction temperature led to a decrease in K. The interactions between dyes and BSA were attributed to static-electricity gravitation which was confirmed by the calculation results of enthalpy and entropy for these reactions. According to the non-radiation energy transfer theory,the acceptor-donor distances and energy transfer efficiencies between dyes and protein at various temperatures were obtained. These results further supported the conclusion that these reactions belonged to the single static quenching which was caused by the energy transfer.