Sealed reticulocyte ghosts. An experimental model for the study of Fe2+ transport.
Sealed right-side-out reticulocyte ghosts transported and accumulated iron offered as 59Fe(2+)-ascorbate (Km = 1.1 microM). The uptake of iron by ghosts presented the characteristics of a transporter-mediated process: it responded to osmotic challenge, the rate of transport increased when iron was present in the opposing side, and the transport rate showed the temperature dependence typical of membrane-mediated processes. The transport of iron was dependent on an associated influx of Cl- in order to keep electroneutrality. Other transition metals, such as Cu2+, Zn2+, and Co2+, inhibited the transport of Fe2+. The overall characteristics of the system make reticulocyte sealed ghosts a very useful model in determining the basic mechanisms of membrane iron transport.
Núñez
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Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, Santiago.
Escobar
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A
Ahumada
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Gonzalez-Sepulveda
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M
D000818:Animals; D000838:Anions; D001692:Biological Transport; D000001:Calcimycin / Q000494:pharmacology; D002413:Cations, Divalent; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D007501:Iron / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D009994:Osmolar Concentration; D009995:Osmosis; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D013696:Temperature
D000838:Anions; D002413:Cations, Divalent; D000001:Calcimycin; D007501:Iron