Abstract
The iron-storage protein ferritin consists of a protein shell and has an iron content of up to 4500 iron atoms as a microcrystalline ferric oxide hydrate. A study was made of the uptake of ferrous iron by apoferritin in the presence of an oxidizing agent at very low iron:protein ratios. At ratios of less than about 150 iron atoms per apoferritin molecule hyperbolic progress curves were obtained, whereas at higher ratios the curves became sigmoidal under the conditions used. A computer model, developed previously (Macara et al., 1972), was shown to account for this result. The experimental evidence indicates that apoferritin binds ferrous iron and catalyses the initial stage in the formation of the ferric oxide hydrate inside the protein shell. This stage involves the oxidation of sufficient iron within the protein molecule to form a stable nucleus on which the growth of the microcrystalline iron-core particles can proceed. A possible schematic mechanism for the action of apoferritin is suggested.
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Selected References
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- Crichton R. R. Structure and function of ferritin. Angew Chem Int Ed Engl. 1973;12(1):57–65. doi: 10.1002/anie.197300571. [DOI] [PubMed] [Google Scholar]
- Fischbach F. A., Anderegg J. W. An x-ray scattering study of ferritin and apoferritin. J Mol Biol. 1965 Dec;14(2):458–473. doi: 10.1016/s0022-2836(65)80196-6. [DOI] [PubMed] [Google Scholar]
- Harrison P. M., Fischbach F. A., Hoy T. G., Haggis G. H. Ferric oxyhydroxide core of ferritin. Nature. 1967 Dec 23;216(5121):1188–1190. doi: 10.1038/2161188a0. [DOI] [PubMed] [Google Scholar]
- Linder-Horowitz M., Ruettinger R. T., Munro H. N. Iron induction of electrophoretically different ferritins in rat liver, heart and kidney. Biochim Biophys Acta. 1970 Mar 31;200(3):442–448. doi: 10.1016/0005-2795(70)90100-5. [DOI] [PubMed] [Google Scholar]
- Macara I. G., Hoy T. G., Harrison P. M. The formation of ferritin from apoferritin. Kinetics and mechanism of iron uptake. Biochem J. 1972 Jan;126(1):151–162. doi: 10.1042/bj1260151. [DOI] [PMC free article] [PubMed] [Google Scholar]