盐酸二氧丙嗪与牛血清白蛋白结合性质研究

Binding Characteristics of Dioxopromethaine Hydrochloride and Bovine Serum Albumin

在模拟生理条件下,利用荧光光谱、紫外-可见吸收光谱及圆二色光谱研究盐酸二氧丙嗪(DPZ)与牛血清白蛋白(BSA)的相互作用.结果表明:DPZ对BSA的内源性荧光有猝灭作用,猝灭的主要原因为静态猝灭.DPZ与BSA以1∶1的摩尔比结合,结合常数Ka分别为:3.664×103(289K)、3.439×103(296 K)、3.257×103(303 K)、2.979×103(310 K).由热力学方程求得该反应的热力学参数表明DPZ与BSA之间的作用力主要为疏水作用力和静电引力.根据Frster偶极-偶极非辐射能量转移理论求得结合距离r=3.161 nm,同步荧光光谱、吸收光谱及圆二色光谱的结果表明DPZ对BSA的构象产生了影响.

The interaction between dioxopromethaine hydrochloride （DPZ） and bovine serum albumin （BSA） under physiological conditions was studied by fluorescence spectroscopy, UV spectra and circular dichroism. The results showed that DPZ remarkably quenched intrinsic fluorescence of BSA. The mecha- nism of fluorescence quenching was confirmed that the combining was brought about by static quenching, and the molar ratio was 1： 1. The binding constants were 3.664 ×10^3 （289 K） ,3.439 ×10^3 （296 K）, 3. 257 ×10^3 （303 K） and 2. 979 ×10^3 （ 310 K）, respectively. The thermodynamic parameters indicated that the electrostatic forces and hydrophobic forces were the main binding forces. According to the Forster the- ory of non-radiation energy transfer, the binding distances （r） were 3.161 nm. The results of Synchronous fluorescence, UV and CD spectra showed that DPZ had effect on the conformation of BSA.