【摘要】 用亲和层析法自黑斑双鳍电鳐电器官提纯出烟碱样乙酰胆碱受体,产率41.1％,比结合力7.3nmol/mg protein。饱和结合分析获得的Scatch-ard曲线呈上凸的抛物线形状,K_D1,K_D2分别为9.63nmol和2.74nmol,Hill系数为1.3。根据氨基酸定量测定值推算,该受体的最小分子量约为220000～230 000;测得其等电点为4.75。在SDS电泳上,纯化受体解离成表观分子量分别为 39000,43000,47000及53000的四条区带,提示它是由多个亚基组成的大分子蛋白。更多还原

【Abstract】 The acetylcholine receptor (AChR) has been purified from the electric organ of the Narcine maculata in the South China Sea by affinity chromatography. The non-degeneracy and the biological activity of the purified receptor have been proved in our studies. In a series of radio ligand binding assay, the purified receptor showed nicotinic receptor characteristics, and the binding maximum for [125I] neuro toxin is about 7.3 nmol/mg protein. In Scatchard plot assay, we found a positive parabolic binding curve, the KD1 and KD2 were 9.6 nmol and 2.7 nmol, respectively, the Hill coefficient was 1.3.The molecular weight of the purified receptor was about at least 220 000-230 000 as calculated from the data of amino acid assay. Its isoelectric point was about pH 4.75 by isoelectrofocusing. In the gels of SDS-electrophoresis, the purified receptor was divided into four protein zones, their apparent molecular weight were 39 000, 43 000, 47 000 and 53 000, respectively. The amino acid composition for the AChR has also been discussed更多还原