氧氟沙星与牛血清白蛋白相互作用机制

THE REACTION MECHANISM BETWEEN OFLOXACIN AND BOVINE SERUM ALBUMIN

摘要: 目的　以光谱技术与微量热技术相结合的方法研究水溶液中牛血清白蛋白与氧氟沙星分子间结合作用的机制。方法　用荧光猝灭法及微量热法。结果　荧光猝灭法测得该反应的结合常数K=1.20×105 L.mol^-1,结合位点数n=1.20,微量热法测得反应的焓变Δ_rH_m≈0;用同步荧光技术考察氧氟沙星对牛血清白蛋白构象的影响;依据Fōrster非辐射能量转移机制,得到授体-受体间的结合距离(r=2.59 nm)和能量转移效率(E=0.38)。结论　牛血清白蛋白与氧氟沙星分子间有较强的结合作用,且结合力以疏水作用为主。

Abstract: AIM　To study the reaction mechanism between ofloxacin and bovine serum albumin (BSA) in aqueous solution. METHODS　Fluorescence spectra and microcalorimetry was used. RESULTS　The binding constant K was found to be 1.20×10⁵ L.mol^-1 and the number of binding site n was 1.20. Microcalorimetric measurements showed that the molar enthalpy change was Δ_rH_m≈0 for the reaction. The effect of ofloxacin on the conformation of BSA was analyzed using synchronous fluorescence spectrometry. The binding distance (r=2.59 nm) and transfer efficiency (E=0.38) between ofloxacin and BSA were also obtained according to the theory of Fōrster′s non-radiation energy transfer. CONCLUSION　The interaction between ofloxacin and BSA is stronger and the main binding force is hydrophobic interactions.