Ferritin heavy chain

Post-Transcriptional Regulation of Ferritin Heavy Chain... 

Joshi JG, Fleming JT, Dhar M, Chauthaiwale VJ (1995) A novel ferritin heavy chain messenger ribonucleic acid in the human brain. J Neurol Sci 134 52-56... 

Stefanini et al. 128) have also attempted to identify which carboxyl-ates form the ferroxidase center, using horse spleen ferritin. Their study, which involved the application of various spectroscopic techniques to chemically modified ferritin, identified Asp 127 and Glu 130, groups present in the threefold channel, as the ferroxidase center. However, studies by Treffry et al. 141) of site-directed mutants of human heavy-chain ferritins indicate that the ferroxidase center is not in the threefold channels. 

Unknowns are the light and heavy chains of ferritin, the iron-storage protein found in animals, plants, and microbes. 

Broxmeyer, H., Cooper, S. Arosio, P, Mutated recombinant human heavy-chain ferrittins and myelosuppression intdviinovivo A link between ferritin ferroxidase activity and biological function. PNAS, 1991.88 p. 770-774. 

Ferritin is a hollow shell containing 24 subunits that are a mixture of heavy (H) and light (L) chains, arranged in octahedral symmetry. The hollow core has a diameter of 8 nm and can hold as many as 4 500 iron atoms in the approximate form of the mineral ferrihydrite (5Fe203 9H2O). Iron(II) enters the protein through any of six pores located on the threefold symmetry axes of the octahedron. Oxidation to Fe(III) takes place at catalytic sites on the H chains. Sites on the inside of L chains appear to nucleate crystallization of ferrihydrite. 

Ferritin is an iron-storage protein, which keeps iron in a safe form within a protein shell. The protein shell of mammalian ferritin is composed of 24 subunits of heavy (H)and light (L) amino acid chains. The external diameter of the protein shell is about 12 nm, and the diameter of the internal cavity is about 7 nm. Inside this cavity up to 4500 ions of iron may be located. Most of the ferritin molecules are not full, but contain varying amounts of iron [IT]. 

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