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化学学报
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化学学报 ›› 2008, Vol. 66 ›› Issue (11): 1366-1370. 上一篇    下一篇

研究论文

氧氟沙星与脲诱导牛血清白蛋白结合的机制研究

唐臻强 易平贵 于贤勇   

  1. 湖南科技大学 湘潭：湘潭工学院化工系 湖南科技大学化学化工学院
  • 投稿日期:2007-03-23 修回日期:2008-01-07 发布日期:2008-06-14
  • 通讯作者: 易平贵

Studies on the Interactional Mechanisms between Oflxacin and Urea-induced Bovine Serum Albumin

Tang Zhen-Qiang Xianyong Yu   

  • Received:2007-03-23 Revised:2008-01-07 Published:2008-06-14

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923

被引次数

10

摘要 利用荧光光谱和紫外光谱研究了脲（Urea）对牛血清白蛋白（BSA）结构的影响以及氧氟沙星（Oflxacin）与脲诱导的BSA结合的情况。结果显示：Urea诱导BSA变性历经两步、三态过程，且伴随中间态的形成。随着Urea浓度的增大，BSA荧光强度降低并先蓝移（344 nm～336 nm），后又红移至350 nm。Urea浓度在4.6～5.2 mol/L范围时，Oflx对BSA中间态有强的猝灭作用（KQ=10.46×104 L/mol, Urea 4.8 mol/L）和较大的结合常数（KA=3.8807×105 L/mol, Urea 4.8 mol/L），但是结合位点数小（n=0.76, Urea 5.0 mol/L），能量传递效率低（E=0.3002, Urea 4.8 mol/L）。同步荧光光谱显示：Urea诱导BSA去折叠时，Trp-212残基微环境并未发生改变，而Tyr的最大荧光发射峰蓝移，Oflx的加入诱导Trp-212的微环境更具疏水性。Oflx加速了Urea对BSA的失活作用。

关键词: 脲, 氧氟沙星, 牛血清白蛋白, 荧光淬灭, 同步荧光

Abstrat: Structural alteration of Urea-induced Bovine serum albumin and interaction of Oflxacin with urea-induced BSA were investigated by UV-vis and fluorescence spectroscopy .The results indicated that BSA followed a two-step, three-state transition with an intermediate in process of unfolding. With increasing the concentration of Urea, it can be found that the fluorescence of BSA decreased with early a blue shift of about 8 nm (from 344 nm to336 nm) and subsequently a red shift to 350 nm. When urea concentrations varied from 4.6 mol/L to 5.2 mol/L, oflx quenched fluorescence of intermediate of BSA with the optimal condition as fluorescence quenching constants (KQ=10.46×104 L/mol，Urea 4.8 mol/L) and binding constants (KA=3.8807×105 L/mol，Urea 4.8 mol/L), whereas with small binding sites（n=0.76，Urea 5.0 mol/L）and low energy transfer efficiency（E=0.3002, Urea 4.8 mol/L）. Synchronous fluorescence spectrometry showed that during unfolding of BSA induced by urea, Trp-212 residue microenvironment has no changes, at the same time the maximal fluorescence peak of Tyr shift towards short-wavelength. The introduction of Oflx indued Trp microenvironment to more hydrophodic. And it also accelerated the denaturation of BSA by urea.

Key words: Urea, Oflxacin, Bovine Serum Albumin, Fluorescence quenching, Synchronous fluorescence