嘧霉胺与牛血清白蛋白结合作用的热力学特征研究

Studies on the interaction thermodynamics features and the ultra-viole absorbance spectra of pyrimethanil

在模拟动物体生理条件下,用荧光猝灭光谱、同步荧光光谱、三维荧光光谱和紫外可见吸收光谱等研究了不同温度下嘧霉胺(Pyrimethanil,简称PMT)与牛血清白蛋白(bovine serum albumin,简称BSA)结合作用的光谱行为.实验表明,PMT对BSA有较强的荧光猝灭作用.用Stern-Volmer方程、Lineweaver-Burk双倒数方程和热力学方程等处理实验数据,得到了在25～44℃温度范围内,结合反应的生成常数K_(LB)(平均值:3.512×104 L·mol^(-1))、热力学参数(平均值:ΔH~θ、ΔG~θ和ΔS~θ分别为-1.534 kJ·mol^(-1)、-26.77 kJ·mol^(-1)和82.01 J·K^(-1))和结合位点数(平均值:1.030);发现PMT与BSA可结合形成具有一定结构的复合物,其荧光猝灭作用更符合静态猝灭作用特征,作用力可能主要是静电力;同时探讨了嘧霉胺对BSA构象的影响.这为研究嘧霉胺的毒理作用、生态环境效应和生物学效应等提供了重要信息.

Under the imitated physiological condition of animal body and different temperatures, the interaction of pyrimethanil （PMT） to bovine serum albumin （BSA） was studied by means of the fluorescence quenching spectrum, synchronous fluorescence spectrum, three-dimensional fluorescence spectrum and ultro-violet spectrum. It was shown that this compound has a quite strong ability to quench the fluorescence launching from BSA. After analyzing the fluorescence quenching data by Stern-Volmer equa- tion, Lineweaver-Burk equation and thermodynamic equation,the average value of bondingconstant（KLB ： 3. 512 × 10^4 L · mol^-1 ）, thermodynamic parameters （△H^θ ： - 1. 534 kJ · mol^-1,△G^θ：-26.77 kJ · mol^-1,△S^θ：82. 01 J · K^-1） and numbers of bonding sites （1. 030） were obtained. It has been proved that BSA can react with pyrimethanil and form a new compounain in this system. The quenching belonged to static fluorescence quenching and action force was static interaction each other,at the same time comforma- tion modification of BSA because added PMT were discussed. It provides important information for studying the toxicity effects of PMT,and entironment effects, and biological effects, etc.