Is hydrogen peroxide produced during iron(II) oxidation in mammalian apoferritins

摘要: The ferritins are a class of iron storage and detoxification proteins that play central role in the biological management iron. These have catalytic site, "the ferroxidase site", located on H-type subunit facilitates oxidation Fe(II) to Fe(III) by O(2). Measurements during past 10 years number vertebrate provided evidence H(2)O(2) is produced at this diiron site. Recently reported experiments using three different analytical methods with horse spleen ferritin (HoSF) failed detect production protein [Lindsay, S., Brosnahan, D., Watt, G. D. (2001) Biochemistry 40, 3340-3347]. findings contrast earlier results reporting HoSF [Xu, B., Chasteen, N. (1991) J. Biol. Chem. 266, 19965-19970]. Here sensitive fluorescence assay an based O(2) evolution presence catalase were used demonstrate as previously reported. However, because relatively few H-chain sites reaction protein, more difficult than recombinant human (HuHF). proper sequence addition reagents important for measurement total amount ferroxidation reaction.