Kinetic studies of iron deposition catalyzed by recombinant human liver heavy, and light ferritins and Azotobacter vinelandii bacterioferritin using O2 and H2O2 as oxidants

Bunker, Jared; Lowry, Thomas Martin; Davis, G. G.; Zhang, Bo; Brosnahan, David; Lindsay, Stuart; Costen, Robert C.; Choi, Sang H.; Arosio, Paolo; Watt, Gerald D.

doi:10.1016/j.bpc.2004.11.008

Cited by 22 publications

(27 citation statements)

References 37 publications

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“…Similar differences in rates for the two oxidants have been reported for HuLF. 31,37 The kinetic differences between the two oxidants in L-rich ferritin were also reflected in a significant difference in the absorbance values of the resultant cores (Figure 5C). The molar absorptivity value of the μ -oxo/hydroxo-Fe(III) core produced by H 2 O 2 was 2200 ± 100 M −1 cm −1 versus 3400 ± 200 M −1 cm −1 for that produced by O 2 as the oxidant, indicating significantly different mineral structures.…”

Section: Resultsmentioning

confidence: 97%

Iron Oxidation and Core Formation in Recombinant Heteropolymeric Human Ferritins

et al. 2017

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In animals, the iron storage and detoxification protein, ferritin, is composed of two functionally and genetically distinct subunit types, H (heavy) and L (light), which co-assemble in various ratios with tissue specific distributions to form shell-like protein structures of 24 subunits within which a mineralized iron core is stored. The H-subunit possesses a ferroxidase center (FC) that catalyzes Fe(II) oxidation, whereas the L-subunit does not. To assess the role of the L-subunit in iron oxidation and core formation, two human recombinant heteropolymeric ferritins, designated H-rich and L-rich with ratios of ~20H:4L and ~22L:2H, respectively, were employed and compared to the human homopolymeric H-subunit ferritin (HuHF). These heteropolymeric ferritins have a composition similar to the composition of those found in hearts and brains (i.e., H-rich) and in livers and spleens (i.e., L-rich). As for HuHF, iron oxidation in H-rich ferritin was found to proceed with a 2:1 Fe(II):O2 stoichiometry at an iron level of 2 Fe(II) atoms/H-subunit with the generation of H2O2. The H2O2 reacted with additional Fe(II) in a 2:1 Fe(II):H2O2 ratio, thus avoiding the production of hydroxyl radical. A μ-1,2-peroxo-diFe(III) intermediate was observed at the FC of H-rich ferritin as for HuHF. Importantly, the H-rich protein regenerated full ferroxidase activity more rapidly than HuHF did and additionally formed larger iron cores, indicating dual roles for the L-subunit in facilitating iron turnover at the FC and in mineralization of the core. The L-rich ferritin, while also facilitating iron oxidation at the FC, additionally promoted oxidation at the mineral surface once the iron binding capacity of the FC was exceeded.

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Section: Resultsmentioning

confidence: 97%

Iron Oxidation and Core Formation in Recombinant Heteropolymeric Human Ferritins

et al. 2017

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“…This proposed reaction might not be as physiologically relevant as reaction at the ferroxidase site, because it is unlikely that the cell experiences these high Fe(II) levels. Nevertheless, attempts to confirm the surface catalysis model have been ongoing, but recent results do not support this reaction and alternative explanations were proposed [12,13].…”

Section: Introductionmentioning

confidence: 84%

“…Considerable evidence using O 2 supports these two processes, but recent results suggest that iron deposition with O 2 is more complicated than originally thought [12,13]. The complications arise because O 2 is reduced to H 2 O 2 , which either reacts with Fe(II) to form mineral core (Fe(II)/O 2 = 4.0) or undergoes secondary reactions with solution components (Fe(II)/O 2 = $2.5).…”

Section: Introductionmentioning

confidence: 84%

“…The FC is found exclusively in the H-subunit so a greater ferroxidase activity is expected and is observed in rHF than in HoSF, using O 2 as an oxidant [37]. rLF only incorporates iron very slowly in air, probably due to the weak ferroxidase activity of the L-subunit [13]. To evaluate the role of the two types of subunits and the effect of FC on iron deposition by large oxidants, we measured the rate of iron deposition in rHF and rLF homopolymers using cyt c and compared with that in HoSF.…”

Section: Iron Deposition In Rhf and Rlf Using Large Oxidantsmentioning

confidence: 90%

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Anaerobic iron deposition into horse spleen, recombinant human heavy and light and bacteria ferritins by large oxidants

Zhang

Watt

2007

Journal of Inorganic Biochemistry

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“…7). This reaction becomes predominant as the amount of Fe(II) atoms increases, and when the core is already formed (Bunker et al 2005). Fig.…”

Section: Iron Mineralization Mechanismsmentioning

confidence: 99%

Biomimetic Materials Synthesis from Ferritin-Related, Cage-Shaped Proteins

Ceci¹,

Morea²,

Fornara³

et al. 2012

Advanced Topics in Biomineralization

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Kinetic studies of iron deposition catalyzed by recombinant human liver heavy, and light ferritins and Azotobacter vinelandii bacterioferritin using O2 and H2O2 as oxidants

Cited by 22 publications

References 37 publications

Iron Oxidation and Core Formation in Recombinant Heteropolymeric Human Ferritins

Iron Oxidation and Core Formation in Recombinant Heteropolymeric Human Ferritins

Anaerobic iron deposition into horse spleen, recombinant human heavy and light and bacteria ferritins by large oxidants

Biomimetic Materials Synthesis from Ferritin-Related, Cage-Shaped Proteins

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