State Key Laboratory of Virology (Ministry of Education), College of Chemistry and Molecule Sciences, Wuhan University, Wuhan 430072, PR China.
J Photochem Photobiol B. 2012 Apr 2;109:1-11. doi: 10.1016/j.jphotobiol.2011.12.010. Epub 2012 Jan 20.
Chlorpyrifos (CPF) is a widely used organophosphate insecticide which could bind with human serum albumin (HSA) and bovine serum albumin (BSA). The binding behavior was studied employing fluorescence, three-dimensional fluorescence, Circular dichroism (CD) spectroscopy, UV-vis absorption spectroscopy, electrochemistry and molecular modeling methods. The fluorescence spectra revealed that CPF causes the quenching of the fluorescence emission of serum albumin. Stern-Volmer plots were made and quenching constants were thus obtained. The results suggested the formation of the complexes of CPF with serum albumins, which were in good agreement with the results from electrochemical experiments. Association constants at 25°C were 3.039 × 10(5) mol L(-1) for HSA, and 0.3307 × 10(5) mol L(-1) for BSA, which could affect the distribution, metabolism, and excretion of pesticide. The alterations of protein secondary structure in the presence of CPF were confirmed by the evidences from UV and CD spectra. Site competitive experiments also suggested that the primary binding site for CPF on serum albumin is close to tryptophan residues 214 of HSA and 212 of BSA, which was further confirmed by molecular modeling.
毒死蜱（CPF）是一种广泛使用的有机磷杀虫剂，可与人体血清白蛋白（HSA）和牛血清白蛋白（BSA）结合。采用荧光、三维荧光、圆二色性（CD）光谱、紫外可见吸收光谱、电化学和分子建模方法研究了结合行为。荧光光谱表明 CPF 导致血清白蛋白的荧光发射猝灭。制作了 Stern-Volmer 图，从而获得了猝灭常数。结果表明 CPF 与血清白蛋白形成了配合物，这与电化学实验的结果一致。25°C 时的结合常数分别为 3.039×10(5)mol L(-1)（HSA）和 0.3307×10(5)mol L(-1)（BSA），这可能会影响农药的分布、代谢和排泄。CPF 存在时蛋白质二级结构的变化通过紫外和 CD 光谱得到证实。位点竞争实验还表明，CPF 在血清白蛋白上的主要结合位点靠近 HSA 的色氨酸残基 214 和 BSA 的 212，这通过分子建模得到了进一步证实。
