Studies on interaction between gatifloxacin and human serum albumin as well as effect of copper(II) on the reaction.
Studies on interaction between gatifloxacin and human serum albumin as well as effect of copper(II) on the reaction.
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DOI：
10.1016/j.saa.2004.11.019
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
Fei Tan;M. Guo;Qin Yu
中科院分区：
文献类型：
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作者：
Fei Tan;M. Guo;Qin Yu
采用荧光光谱法研究了加替沙星（GTFX）与人血清白蛋白（HSA）在水溶液中的结合特性，并探讨了Cu（II）对GTFX与HSA相互作用的影响。结果表明，GTFX与Cu ~（2+）的双反应平衡常数K=1.16× 105 lmol −1，结合位点数n=1.27; GTFX与Cu ~（2+）的双反应平衡常数K=1.62× 105 lmol −1，结合位点数n=1.74。GTFX对人血清白蛋白的荧光猝灭机理为静态猝灭。根据Fōrster光谱能量转移理论，计算了GTFX与HSA的结合距离和能量转移效率。用同步荧光光谱分析了GTFX对HSA构象的影响。用流动混合微量热法研究了GTFX与HSA在Cu（II）存在和不存在下的相互作用，得到了它们的热力学参数。在无Cu（II）存在下，GTFX与HSA相互作用的焓变和熵变分别为ΔH <$0，ΔS>0，表明静电力在GTFX与HSA相互作用中起主要作用;在有Cu（II）存在下，GTFX与HSA相互作用的焓变和熵变分别为ΔH <$0，ΔS>0，表明静电力在GTFX与HSA相互作用中也起主要作用。两个反应的摩尔自由能变化基本一致，这是因为两个反应之间存在熵-焓补偿。
The binding characteristics of gatifloxacin (GTFX) and human serum albumin (HSA) have been studied by fluorescence spectroscopy in aqueous solution, and the interaction influenced by copper(II) was also explored in the paper. The results show that the two-reaction equilibrium constant and the number of binding sites were K=1.16×105lmol−1, n=1.27 for GTFX and K=1.62×105lmol−1, n=1.74 for GTFX–Cu2+, respectively. The quenching mechanism of fluorescence of HSA by GTFX is a static quenching procedure. The binding distance between GTFX and HSA and the energy transfer efficiency are obtained based on the theory of Fōrster spectroscopy energy transfer. The effect of GTFX on the conformation of HSA was also been analyzed by using synchronous fluorescence spectroscopy. The interaction of GTFX and HSA has been studied by flow-mixed microcalorimetry in the absence and presence of copper(II) and their thermodynamic parameters were obtained. The enthalpy changes and the entropy changes were calculated to be ΔH≈0, ΔS>0 in the absence of copper(II),which indicated that static forces played major role in the interaction of GTFX and HSA, and to be ΔH≈0, ΔS>0 in the presence of copper(II),which indicated that the static forces also played major role on the reaction. The molar free energy changes of the two reactions are identical with each other because the entropy–enthalpy compensation happened between the two reactions.