title: Binding of transferrin and uptake of iron by K-562 cells.
abstract: Transferrin-mediated uptake of iron has been studied in K-562 human erythroleukaemia cells. K-562 cells accumulate iron from transferrin by a temperature-dependent mechanism linearly with time for at least 150 min. At 37 degrees C the uptake reaches a saturation level of approximately 25 pmol iron/10(6) cells/h at a concentration of iron (as iron-transferrin) of 5 mumol/l. The binding of transferrin reveals saturation kinetics, at 0.2 mumol/l of transferrin specific binding amounts to 1.8 pmol/10(6) cells. Relative to the binding of transferrin the uptake of iron increases with time. The ability of K-562 cells to accumulate iron declines with days in culture by approximately 50% from day 1 to day 5. The results are compatible with iron uptake by receptor-mediated endocytosis of transferrin, dissociation of iron within the cell and exocytosis of apotransferrin.
mesh_terms: D002460:Cell Line; D006801:Humans; D007501:Iron / Q000378:metabolism*; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011990:Receptors, Transferrin; D013696:Temperature; D013997:Time Factors; D014168:Transferrin / Q000378:metabolism*
chemical_list: D011956:Receptors, Cell Surface; D011990:Receptors, Transferrin; D014168:Transferrin; D007501:Iron