Estrogen Receptor Binding Assay Method for Endocrine Disruptors Using Fluorescence Polarization
作者:Ken-ichi Ohno、Takeshi Fukushima、Tomofumi Santa、Nobuaki Waizumi、Hidetoshi Tokuyama、Masako Maeda、Kazuhiro Imai
DOI:10.1021/ac020088u
日期:2002.9.1
A rapid, simple and nonhazardous assay method for endcrine disruptors was developed using an estrogen receptor (ER) and fluorescence polarization (FP). Among the fluorescent compounds, the 17α-fluorescein-labeled estradiol derivative was selected as the most suitable ligand for the ER binding assay, since it showed the highest affinity to ER. In the Scatchard plot analysis, its convex curve exhibited a positive cooperative binding, indicating the induction of a conformational change of the ER with the binding of the ligand to form a dimer and to increase the affinity for the additional ligand. On the basis of the Hill plot analysis, its dissociation constant and Hill coefficient were 10.4 nM and 1.63, respectively. A competitive binding assay with an unlabeled 17β-estradiol (E2) yielded an IC50 value of 2.82 nM and a Hill coefficient of 1.67, thus providing a Ki value of 0.65 nM. In the same manner, the Hill coefficients for estrone, estriol, diethylstilbestrol, and tamoxifen were determined to be 0.99, 1.17, 1.59, and 2.44, respectively.
开发了一种快速、简单且无害的内分泌干扰物检测方法,该方法使用雌激素受体(ER)和荧光偏振(FP)。在荧光化合物中,选择17α荧光素标记的雌二醇衍生物作为最适合的ER结合检测配体,因为它对ER表现出最高的亲和力。在Scatchard图分析中,其凸曲线显示出正合作结合,表明配体结合后诱导了ER构象的变化,从而形成二聚体并增加对额外配体的亲和力。根据Hill图分析,其解离常数为10.4 nM,Hill系数为1.63。与未标记的17β-雌二醇(E2)进行的竞争结合实验得到IC50值为2.82 nM,Hill系数为1.67,从而提供了Ki值为0.65 nM。同样,雌酮、雌三醇、二乙基苯酮和他莫昔芬的Hill系数分别确定为0.99、1.17、1.59和2.44。