BINDING OF Fe2+ BY MAMMALIAN FERRITIN
نویسندگان
چکیده
An average of 140 Fe 2 + ions bind to mammalian ferritin that has an average core content of 1876 Fe+ ions per molecule. The Fe2+ ions enter the protein interior and exchange electrons with the core Fe+ ions. A non-homogeneous model for the iron-eontaining core of ferritin is proposed.
منابع مشابه
Redox reactivity of bacterial and mammalian ferritin: is reductant entry into the ferritin interior a necessary step for iron release?
Both mammalian and bacterial ferritin undergo rapid reaction with small-molecule reductants, in the absence of Fe2+ chelators, to form ferritins with reduced (Fe2+) mineral cores. Large, low-potential reductants (flavoproteins and ferredoxins) similarly react anaerobically with both ferritin types to quantitatively produce Fe2+ in the ferritin cores. The oxidation of Fe2+ ferritin by large prot...
متن کاملKinetics and Mechanism of Iron Uptake
Ferritin has a high capacity as an iron store, incorporating some 4500 iron atoms as a microcrystalline ferric oxide hydrate. Starting from apoferritin, or ferritin of low iron content, Fe2+ and an oxidizing agent, the uptake of iron can be recorded spectrophotometrically. Progress curves were obtained and the reconstituted ferritin was shown by several physical methods to be similar to natural...
متن کاملReduction of mammalian ferritin.
Mammalian ferritin from horse spleen undergoes an electrochemical or chemical reduction reaction in which each iron atom present is reduced by one electron (2300 electrons per ferritin molecule containing 2300 Fe3+ ions). Midpoint potentials of -190 mV, -310 mV, and -416 mV were determined at pH 7.0, 8.0, and 9.0. This variation of potential with pH indicates that approximately 2 H+ are transfe...
متن کاملFerroxidase kinetics of horse spleen apoferritin.
Protein ferroxidase site(s), which catalyze the reaction between ferrous ion and dioxygen, have long been thought to play a role in core formation in ferritin; however, the mechanism of the reaction has never been studied in detail. In the present work, the enzymatic activity of ferritin was examined using oximetry, the net Fe2+ oxidation reaction being as follows. [formula: see text] The react...
متن کاملRate of iron transfer through the horse spleen ferritin shell determined by the rate of formation of Prussian Blue and Fe-desferrioxamine within the ferritin cavity.
Iron (2+ and 3+) is believed to transfer through the three-fold channels in the ferritin shell during iron deposition and release in animal ferritins. However, the rate of iron transit in and out through these channels has not been reported. The recent synthesis of [Fe(CN)6]3-, Prussian Blue (PB) and desferrioxamine (DES) all trapped within the horse spleen ferritin (HoSF) interior makes these ...
متن کامل