荧光光谱法研究头孢硫脒与牛血清白蛋白的相互作用

在模拟生理条件下,用荧光光谱法和紫外-可见吸收光谱法研究头孢硫脒和牛血清白蛋白(BSA)结合反应的特征。研究表明:头孢硫脒与牛血清白蛋白形成复合物,从而猝灭BSA的内源性荧光,该过程为静态猝灭过程。根据Stern-Volmer方程得出了不同温度下结合位点数n和结合常数Ka;结合位点位于BSA的亚结构ⅡA中。通过计算相应的热力学参数,确定了头孢硫脒与牛血清白蛋白之间的作用力主要为氢键和范德华力。利用同步荧光光谱探讨了头孢硫脒与BSA作用前后BSA的构型变化。Hill系数nH<1,表明头孢硫脒有弱的负协同作用。此研究不仅对于揭示体内药物动力学问题和指导临床合理用药具有一定意义,而且对药物分子设计及新药开发等也具有重要指导意义。

Study on the Interaction between Cefathiamidine and Bovine Serum Albumin by Fluorescence Spectroscopy

The interaction between cefathiamidine and bovine serum albumin （BSA） was studied with fluorescence spectra and UV - visible absorption spectra in the presence of simulating physiological systems. It showed that the complex for mated by BSA and cefathiamidine lead to the static quenching of the intrinsic fluorescence of BSA. The binding site number n and apparent binding constant Ka were measured according to Stern - Volmer equation. The distance between BSA and cefathia- midine was obtained based on the FOrster nonradiative energy transfer theory. We also confirmed that the main sorts of bind- ing force between cefathiamidine and BSA is Hydrogen bond and Vander Waals force. Meanwhile, synchronous fluorescence was used to investigate the structure change of BSA before and after the introduction of cefathiamidine. The primary binding site for cefathiamidine was located at site Ⅰ in subdomain Ⅱ A of BSA. It is not only valuable to reveal the pharmacokinetics, clinical therapy, but also guiding significance for drug design and development of new drugs.