Huebers H A, Csiba E, Huebers E, Finch C A
Proc Natl Acad Sci U S A. 1983 Jan;80(1):300-4. doi: 10.1073/pnas.80.1.300.
Radioiron- and radioiodine-labeled forms of human diferric and monoferric transferrin and apotransferrin, isolated by preparative isoelectric focusing, were used to define transferrin-iron uptake by human reticulocytes. In mixtures of human diferric and monoferric transferrin, the diferric molecule had a constant 7-fold advantage in delivering iron to reticulocytes, as compared with the 2-fold advantage when single solutions of mono- and diferric transferrins were compared. This was shown to be due to competitive interaction in iron delivery, probably at a common membrane-receptor binding site for transferrin. Apotransferrin did not interfere with the iron-donating process and its limited cellular uptake was inhibited in noncompetitive fashion by diferric transferrin.
通过制备性等电聚焦分离得到的人双铁和单铁转铁蛋白及脱铁转铁蛋白的放射性铁和放射性碘标记形式，被用于确定人网织红细胞对转铁蛋白-铁的摄取。在人双铁和单铁转铁蛋白的混合物中，与分别比较单铁和双铁转铁蛋白单一溶液时2倍的优势相比，双铁分子在将铁递送至网织红细胞方面具有恒定的7倍优势。这表明这是由于铁递送过程中的竞争性相互作用，可能是在转铁蛋白共同的膜受体结合位点。脱铁转铁蛋白不干扰铁的捐赠过程，其有限的细胞摄取受到双铁转铁蛋白非竞争性方式的抑制。
