人红细胞膜中d-α-生育酚特异性结合位点的表征与增溶

Characterization and solubilization of the specific binding sites for d-alpha-tocopherol from human erythrocyte membranes.

作者信息

Wimalasena J, Davis M, Kitabchi A E

出版信息

Biochem Pharmacol. 1982 Nov 1;31(21):3455-61. doi: 10.1016/0006-2952(82)90626-8.

Abstract

Previous work from our laboratory has demonstrated the presence of specific binding sites for d-alpha-tocopherol (vitamin E) in intact human erythrocytes [A. E. Kitabchi and J. Wimalasena, Biochim. biophys. Acta 684, 300 (1982)]. The binding was time, temperature and cell concentration dependent. To localize the binding sites, red blood cells were further fractionated; greater than 90% of the tocopherol binding sites were localized on membranes. The washed membrane fraction from normal human erythrocytes has specific binding sites for d-alpha-tocopherol with properties suggestive of protein receptors. Two binding sites with Ka values of 3.31 x 10(1)M-1 and 1.51 x 10(6)M-1 were demonstrated, and solubilized d-alpha-tocopherol binding site complexes were resolved to a major component with an Mr of 65,000 and a minor component with an Mr of 125,000.

摘要

我们实验室之前的研究已经证明，在完整的人红细胞中存在d-α-生育酚（维生素E）的特异性结合位点[A. E. 基塔奇和J. 维马拉塞纳，《生物化学与生物物理学学报》684, 300 (1982)]。这种结合具有时间、温度和细胞浓度依赖性。为了确定结合位点的位置，对红细胞进行了进一步分级分离；超过90%的生育酚结合位点位于细胞膜上。来自正常人红细胞的洗涤膜组分具有d-α-生育酚的特异性结合位点，其性质提示为蛋白质受体。已证明有两个结合位点，其解离常数（Ka）值分别为3.31×10¹M⁻¹和1.51×10⁶M⁻¹，并且溶解的d-α-生育酚结合位点复合物被解析为一个主要成分，其相对分子质量（Mr）为65,000，还有一个次要成分，Mr为125,000。