氯酚与乙酰胆碱酯酶相互作用的光谱研究

采用荧光光谱法和紫外-可见光谱法研究了2,4,6-三氯酚(2,4,6-TCP)及五氯酚(PCP)与乙酰胆碱酯酶(AChE)的相互作用,获得了相互作用的Stern-Volmer猝灭常数、结合常数、热力学参数和作用距离.结果表明, 2,4,6-TCP及PCP均可以使AChE内源荧光有规律地猝灭,温度小于303K时,其猝灭机制为静态猝灭. 2,4,6-TCP及PCP与AChE的结合过程是受熵驱动的自发过程,作用力为典型的疏水作用力. 2,4,6-TCP及PCP与AChE分子中酪氨酸残基的作用距离分别为1.91,2.00nm, 2,4,6-TCP及PCP与AChE分子的结合常数为104~105L/mol,表明2种氯酚与AChE之间发生了非辐射能量转移,两者形成了稳定的复合物.2,4,6-TCP与AChE的结合作用比PCP与AChE的结合作用强,氯酚分子向AChE分子疏水空腔的结合过程是疏水性效应和空间位阻效应彼此竞争的结果.

Interaction between chlorophenols and acetycholinesterase determined by spectroscopic methods

The interaction of acetycholinesterase (AChE) with 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) was studied by fluorescence and UV-Vis spectroscopy. The Stern-Volmer quenching constants, binding constants, thermodynamic parameters and binding distance were obtained. The intrinsic fluorescences of AChE were quenched regularly by 2,4,6-TCP and PCP, respectively. Static quenching mechanism played the major roles when the temperature was less than 303K. The thermodynamic parameters indicated that the binding reaction was spontaneous and being driven by entropy, and the hydrophobic force played the major roles in the binding of AChE and chlorophenols. The binding distance r between AChE and chlorophenols was 1.91 nm for 2,4,6-TCP and 2.00 nm for PCP, respectively. The binding constants of AChE with 2,4,6-TCP and PCP were in the range of 104~105L/mol. Energy transfer from AChE to 2,4,6-TCP and PCP occurred, and the AChE-chlorophenols complex was formed. The binding reaction between 2,4,6-TCP and AChE was stronger than those between PCP and AChE, which was attributed to the competition between hydrophobic effect and stereo-hindrance effect.