Using isotopic labeling of human serumapotransferrin, the binding and the endocytosis of monoter-bium transferrin (TbC-apotransferrin, TbC-apotransferrin-FeN) by K562 cells, a human leukemic cell line, have beeninvest...Using isotopic labeling of human serumapotransferrin, the binding and the endocytosis of monoter-bium transferrin (TbC-apotransferrin, TbC-apotransferrin-FeN) by K562 cells, a human leukemic cell line, have beeninvestigated. There are about (8.58±2.41)×105 binding sites per cell surface at 0℃. The association constant for TbC-apotransferrin binding is 4.1×107 mol-1·L, for TbC-apotransferrin-FeN 2.7×107 mol-1·L at 0℃. At pH 7.4, upon warming cells to 37℃, endocytosis starts. The rate constantsfor the endocytosis are about 0.97 min-1 and 0.31 min-1 and the endocytosis ratio reaches 56% and 80% for TbC-apotransferrin and TbC-apotransferrin-FeN, respectively.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 20071022) and the Natural Science Foundation of Shanxi Province (Grant No. 991013).
文摘Using isotopic labeling of human serumapotransferrin, the binding and the endocytosis of monoter-bium transferrin (TbC-apotransferrin, TbC-apotransferrin-FeN) by K562 cells, a human leukemic cell line, have beeninvestigated. There are about (8.58±2.41)×105 binding sites per cell surface at 0℃. The association constant for TbC-apotransferrin binding is 4.1×107 mol-1·L, for TbC-apotransferrin-FeN 2.7×107 mol-1·L at 0℃. At pH 7.4, upon warming cells to 37℃, endocytosis starts. The rate constantsfor the endocytosis are about 0.97 min-1 and 0.31 min-1 and the endocytosis ratio reaches 56% and 80% for TbC-apotransferrin and TbC-apotransferrin-FeN, respectively.
