【摘要】 在模拟人体生理条件下,利用荧光光谱法、紫外吸收光谱法、圆二色谱法和三维荧光光谱法等方法研究了2,4-二氯苯酚(DCP)与人血清白蛋白(HSA)的相互作用。结果表明,DCP使HSA的荧光强度发生了静态猝灭。根据修正的Stern-Vol mer方程,求出DCP与HSA在292 K、298 K、304 K、310 K下的有效猝灭常数Ka分别为1.1407×105L·mol-1、1.0787×105L·mol-1、1.0389×105L·mol-1和9.760×104L·mol-1。并得到结合过程的热力学参数ΔH和ΔS分别为-6.336 kJ.mol-1和75.12 J·mol-1·K-1,表明静电作用力是维持复合物DCP-HSA稳定的主要作用力。位点竞争实验表明,DCP在HSA上的主要结合位置为SiteⅠ。圆二色谱和三维荧光光谱分析发现,DCP使HSA的α-螺旋结构的含量减少,导致蛋白质多肽链发生轻微解旋,HSA的构象和所处微环境发生了一定程度的变化。更多还原

【Abstract】 The interaction between 2,4-dichlorophenol(DCP) and human serum albumin(HSA) was investigated by spectroscopic techniques including fluorescence spectroscopy,UV-Vis absorption spectrometry,circular dichroism(CD) spectroscopy and three-dimensional fluorescence spectroscopy under simulative physiological conditions.The experiment results showed that the fluorescence intensity of HSA was dramatically decreased owing to a static quenching.According to the modified Stern-Volmer equation,the effective quenching constants between DCP and HSA at four different temperatures(292 K,298 K,304 K and 310 K) were determined to be 1.1407× 105 L ·mol-1,1.0787×105 L ·mol-1,1.0389×105 L ·mol-1 and 9.760×104 L ·mol-1,respectively.The thermodynamics parameters enthalpy change(ΔH) and entropy(ΔS) were calculated to be-6.336 kJ ·mol-1 and 75.12 J ·mol-1 ·K-1,which indicated that electrostatic force was the predominant intermolecular force in stabilizing the complex.Site marker competitive experiment indicated that the binding of DCP to HSA primarily took place in siteⅠ.Circular dichroism and three-dimensional fluorescence spectroscopy revealed that the presence of DCP decreased the α-helical content of HSA and induced a slight unfolding of the polypeptides of protein,which confirmed the occurrence of some micro environmental and conformational changes of HSA molecules.更多还原