HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Muir, W. A. Articles by King, M. Search for Related Content PubMed PubMed Citation Articles by Muir, W. A. Articles by King, M. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 259, Issue 8, 4896-4903, Apr, 1984

Iron transport across brush-border membranes from normal and iron- deficient mouse upper small intestine

WA Muir, U Hopfer and M King

We have studied Fe(III)-citrate and Fe(II)-ascorbate uptake by purified intestinal brush-border membrane vesicles from normal (iron-replete) and iron-deficient mice. In iron-replete mice using a final Fe(III) concentration of 1.43 microM, 25-30 pmol of Fe(III)/mg of protein were bound to the membranes versus 65-70 pmol in iron-deficient mice. Fe(II) uptake in normal mice using a final Fe(II) concentration of 1.79 microM was 1600-1800 pmol/mg of protein versus 3600-4000 pmol in iron- deficient mice. Evidence that Fe(II) was transported into the vesicles by a membrane carrier-mediated process was obtained by observing saturation kinetics under conditions of isotope exchange at equilibrium in mice rendered iron-deficient, but not in iron-replete mice. Eighty per cent of the transported Fe(II) could be removed by strong chelating agents. The remainder was exchangeable with Fe(II) in the medium when measured under equilibrium conditions. We can explain these results by the following model; iron uptake appears to be a 2-fold process. The first step is the transport of Fe(II) across the membrane by a carrier- mediated process which is biologically regulated. The second step is the subsequent binding of iron on the inside of the membrane. The number of binding sites is also regulated by the iron status of the mouse. The membrane binding affinity for Fe(II) appears to be weaker than that for dithiothreitol but stronger than for ascorbate.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				A. J. Ghio, E. Nozik-Grayck, J. Turi, I. Jaspers, D. R. Mercatante, R. Kole, and C. A. Piantadosi Superoxide-Dependent Iron Uptake: A New Role for Anion Exchange Protein 2 Am. J. Respir. Cell Mol. Biol., December 1, 2003; 29(6): 653 - 660. [Abstract] [Full Text] [PDF]

				X. Wang, A. J. Ghio, F. Yang, K. G. Dolan, M. D. Garrick, and C. A. Piantadosi Iron uptake and Nramp2/DMT1/DCT1 in human bronchial epithelial cells Am J Physiol Lung Cell Mol Physiol, May 1, 2002; 282(5): L987 - L995. [Abstract] [Full Text] [PDF]

				F. Canonne-Hergaux, S. Gruenheid, P. Ponka, and P. Gros Cellular and Subcellular Localization of the Nramp2 Iron Transporter in the Intestinal Brush Border and Regulation by Dietary Iron Blood, June 15, 1999; 93(12): 4406 - 4417. [Abstract] [Full Text] [PDF]

				G. Perewusnyk and F. Funk Iron Uptake by Rabbit Intestinal Brush Border Membrane Vesicles Involves Movement Through the Outer Surface, Membrane Interior, Inner Surface and Aqueous Interior J. Nutr., June 1, 1997; 127(6): 1092 - 1098. [Abstract] [Full Text]

				J. N. Umbreit, M. E. Conrad, L. N. Hainsworth, and M. Simovich The ferrireductase paraferritin contains divalent metal transporter as well as mobilferrin Am J Physiol Gastrointest Liver Physiol, March 1, 2002; 282(3): G534 - G539. [Abstract] [Full Text] [PDF]