Phosphorus and the Ferritin Iron Core: Function-Balanced Biomineralization
In the biomineralization of storage iron, the proteins ferritin and hemosiderin sequester iron in a mineral form of colloidal dimensions ( <80 Å). This mineral is the metastable hydrous ferric oxide ferrihydrite (5Fe2O3·9H2O). Ferrihydrite represents an appropriate mineralogical choice to balance the important but opposing physiological functions of iron storage; and iron mobility. The ferrihydrite in both ferritin and hemosiderin contains important amounts of non-structural phosphorus adsorbed to the crystallite surfaces. Experimental data support the suggestion that this phosphorus can act to preserve the role of iron mobility by inhibiting the potential during iron storage for inversion of the more readily soluble, metastable ferrihydrite to one of the less soluble, more stable phases such as goethite (αFeOOH) or hematite (αFe2O3).
KeywordsDifferential Thermal Analysis Iron Storage Ferric Oxide Iron Core Ferric Hydroxide
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- CHUKROV, F.V., ZVYAGIN, B.B., GORSCHKOV, A, YERMILOVA, L.P., and RUDNITSKAYA, E.S., 1971. The Towe-Bradley phase - a product of the supergene alteration of ores. Izvestiya Akademii Nauk SSSR, seriya geologicheskaya, no. 1.Google Scholar
- CHUKROV, F.V., ZVYAGIN, B.B., GORSCHKOV, A, YERMILOVA, L.P., and BALASHOVA, V.V., 1973. Oferrigidrite. Izvestiya Akademii Nauk SSSR, seriya geologicheskaya, no. 4, 23–33.Google Scholar
- GRANICK, S., 1942. Ferritin. I. Physiological and chemical properties of horse spleen ferritin. Journal of Biological Chemistry, 146, 451–461.Google Scholar
- HARRISON, P.M., 1969. The biochemistry of iron. In Iron Metabolism and Anemia, Pan American Health Organization, Scientific Publication No. 184, 2–20.Google Scholar
- HARRISON, P.M. and I IOY, T.G., 1973. Ferritin. In Inorganic Biochemistry, vol. 1 (ed. G.L. Eichhorn ), pp. 253–279. Amsterdam: Elsevier.Google Scholar
- LANGMUIR, D., 1969. The Gibbs free energies of substances in the system Fe-02-H2O-CO2 at 25°C. U.S. Geological Survey Professional Paper 650-B, B180–B184.Google Scholar
- MACKENZIE, R.C., 1952. Investigations on cold-precipitated hydrated ferric oxide and its origin in clays. In Problems of Clay and Laterite Genesis, pp. 65–75, New York: American Institute of Mining Engineers.Google Scholar
- MANSOURI, A.N., THOMPSON, C., TIIEIL, E.C., CHASTEEN, N.D., and SAYERS, D.E., 1985. Fe(III) ATP complexes: models for ferritin and other polynuclear iron complexes with phosphate. Journal of Biological Chemistry, 260, 7975–7979.Google Scholar
- TREFFRY,A. and HARRISON, P.M., 1978. Incorporation and release of inorganic phosphate in horse spleen ferritin. Biochemical Journal, 171, 313–320.Google Scholar