鉄の腸管吸収の担体としてのトランスフェリンレセプターおよびレセプターの集合体形成について
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概要
- 論文の詳細を見る
Although iron is an essential element in animal kingdom, the poor solubility of Fe^<+++> in neutral solution have brought difficulties in assimilation of iron into organisms. Transferrin (iron binding protein) in blood plasma and transferrin receptor on cell membrane are the two main tools equipped by evolution of animals absorbing iron from external environment to blood and finally to cells. My colleagues Mugitani and Hisayasu found out 1/10 concentration of transferrin in rat pancreatic juice referring to that in blood plasma. Specific binding of diferric transferrin to brush border membrane vesicles was calculated by Scatchard analysis (Ka: 1.08x10^8M^<-1>). Iron absorption of ^<59>Fe - diferric transferrin was 27.4% in upper small intestine and that was inhibited either by 20 fold unlabeled diferric transferrin or monodansylcadaverine (MDC), an inhibitor of endocytosis. These results suggest that the receptor mediated endocytosis of diferric transferrin may participate iron absorption in rat intestine. Another colleague Taguchi isolated transferrin receptor from human placenta obtained immediately after delivery. The receptor showed 90K molecular weight by subunit analysis using SDS PAGE. However the molecular weights measured by gel filtration HPLC were 180K (dimers) and its integral numbers, which were made up mainly by 370K component. The assembly of the receptors may indicate the concentration of iron in an endocytotic vesicle and the efficient iron transport into cells.
- 昭和女子大学の論文
- 1992-12-15