19229-76-6Relevant academic research and scientific papers
Protein-Template-Driven Formation of Polynuclear Iron Species
Malone, Simon A.,Lewin, Allison,Kilic, Mehmet A.,Svistunenko, Dimitri A.,Cooper, Chris E.,Wilson, Michael T.,Le Brun, Nick E.,Spiro, Stephen,Moore, Geoffrey R.
, p. 496 - 504 (2004)
Ferritins are iron-storage proteins capable of holding up to 4500 Fe 3+ ions within a single water-soluble protein shell made from 24 polypeptide chains. The Glu128Arg/Glu135Arg mutants of Escherichia coli and Rhodobacter capsulatus bacterioferritins are unable to associate into 24-meric structures, with dimers of polypeptide chains being their stable forms. The aerobic addition to these of up to 8-10 or 14-20 Fe2+ ions per dimer, respectively, results in the oxidation of the added Fe2+ to Fe 3+. Gel permeation chromatography and sedimentation equilibrium studies confirm that the Fe3+ ions are associated with the polypeptide dimer, and the lack of intense EPR signals from magnetically isolated Fe3+ ions confirms the formation of one or more antiferromagnetically coupled clusters of Fe3+ ions. The effect of Fe3+ chelators on iron-loaded subunit dimers is to remove the Fe 3+ from the protein, but to do so slowly, consistent with it not being merely adventitiously associated with protein. These data provide experimental support for the presence of nucleation centers for the mineral cores in bacterioferritins and indicate that these proteins are not simply acting as vessels in which hydrolysis of Fe3+ occurs independent from the protein surface. From analyses of X-ray structures and amino acid sequence comparisons, possible nucleation sites are identified.
Characterisation of chemically lithiated heat-treated electrolytic manganese dioxide
Dose, Wesley M.,Lehr, Joshua,Donne, Scott W.
, p. 1827 - 1834 (2012)
Heat treated manganese dioxide is partially lithiated using butyl-lithium to determine the changes in crystal structure, chemical composition and morphology upon reduction, as a means of simulating its discharge behaviour in a non-aqueous battery cathode. As reduction proceeds, and lithium ions are inserted into the heat treated electrolytic manganese dioxide (EMD) structure, the material undergoes a phase transition to LiMn2O4. This new phase is further reduced to Li2Mn2O4. Reduction initially results in a 56% decrease in the surface area of the material; however, at higher degrees of reduction a slight increase in this value is observed, as a consequence of the strain placed on the lattice through continued lithium insertion.
Redox processes in water, initiated by electric discharge over its surface
Piskarev
, p. 1536 - 1537 (2001)
The yields of oxidation and reduction in a flash corona discharge between a solid cathode and the water surface are compared. As the cathode was used a system of five aluminum electrodes. As the gas medium were tested air, oxygen, and nitrogen. The models of processes in the discharge suggest formation of atomic hydrogen in water vapor: H2O → H + OH. However, the reduction yield is equal to the Faraday value irrespective of the gas composition. In the presence of oxygen, oxidation prevails. The yield of Fe2+ oxidation in oxygen is about 190 reaction events per electron passed in the circuit; in air it is lower by a factor of 2, and in nitrogen the yield is equal to the Faraday value.
On the highest oxidation states of plutonium in alkali solutions in the presence of ozone
Nikonov,Gogolev,Tananaev,Myasoedov
, p. 340 - 342 (2004)
During ozonation of Pu(VI) alkaline solutions, the highest oxidation state of Pu is formed in an oscillatory reaction. This plutonium species is reduced with Pu(VI) or Fe(III). Ferrate ion is also reduced with Pu(VI). It was assumed that in alkali solutio
Drosophila multicopper oxidase 3 is a potential ferroxidase involved in iron homeostasis
Wang, Xudong,Yin, Sai,Yang, Zhihao,Zhou, Bing
, p. 1826 - 1834 (2018)
Multicopper oxidases (MCOs) are a specific group of enzymes that contain multiple copper centers through which different substrates are oxidized. Main members of MCO family include ferroxidases, ascorbate oxidases, and laccases. MCO type of ferroxidases is key to iron transport across the plasma membrane. In Drosophila, there are four potential multicopper oxidases, MCO1–4. No convincing evidence has been presented so far to indicate any of these, or even any insect multicopper oxidase, to be a ferroxidase. Here we show Drosophila MCO3 (dMCO3) is highly likely a bona fide ferroxidase. In vitro activity assay with insect-cell-expressed dMCO3 demonstrated it has potent ferroxidase activity. Meanwhile, the ascorbate oxidase and laccase activities of dMCO3 are much less significant. dMCO3 expression in vivo, albeit at low levels, appears mostly extracellular, reminiscent of mammalian ceruloplasmin in the serum. A null dMCO3 mutant, generated by CRISPR/Cas9 technology, showed disrupted iron homeostasis, evidenced by increased iron level and reduced metal importer Mvl expression. Notably, dMCO3-null flies phenotypically are largely normal at normal or iron stressed-conditions. We speculate the likely existence of a similar iron efflux apparatus as the mammalian ferroportin/ferroxidase in Drosophila. However, its importance to fly iron homeostasis is greatly minimized, which is instead dominated by another iron efflux avenue mediated by the ZIP13-ferritin axis along the ER/Golgi secretion pathway.
Solvent extraction of some trace metals and iron with N-octyl-N,N- bis(dihexylphosphinylmethyl)amine
Cherkasov,Garifzyanov,Bazanova,Leont'eva
, p. 2080 - 2087 (2011)
The processes were studied of the solvent extraction of the ions of triply-charged trace elements including scandium, indium, gallium, and yttrium, as well as iron, with N-octyl-N,N-bis(dihexylphosphinylmethyl)amine solution in toluene, chloroform or methylene chloride from hydrochloric, nitric or perchloric acids aqueous solutions. The metals extraction dependence on the acid concentration showed that the best results were reached using perchloric acid. The calculation of partition coefficients of metals allowed us to reveal a high selectivity of the scandium extraction. The prospects of using the investigated bisphosphinylamine in the technology of extraction, concentration and separation of the trace metals ions was concluded. Pleiades Publishing, Ltd., 2011.
Kinetics and mechanism of oxidation of Fe2+ by the tris(biguanide)manganese(IV) ion in aqueous acid media
Dhar, Basab Bijayi,Mukherjee, Ritam,Mukhopadhyay, Subrata,Banerjee, Rupendranath
, p. 2950 - 2955 (2004)
Tris(biguanide)manganese(IV), [Mn(LH2)3]4+ (LH2 = biguanide, C2N5H7), quantitatively oxidises Fe2+ to Fe3+ and is itself reduced to Mn2+ with almost quantitative (> 95%) release of biguanide, The reaction rate strongly depends on added Fe3+; in the presence of externally added Fe3+, the reaction shows a clear first-order dependence in [MnIV], whereas in the absence of any added Fe 3+, an initial quick loss of MnIV is associated with a subsequent very sluggish decay. Two consecutive one-electron transfer inner-sphere steps are proposed for the entire redox process where [Mn(LH 2)3]3+, the initial one-electron-reduced product of MnIV, is believed to be a steady-state intermediate. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
The special features of the kinetics of oxidation of divalent iron during sulfuric acid leaching of pyrrhotine with the participation of nitrous acid
Markovich
, p. 25 - 28 (2009)
The kinetics of oxidation of divalent iron ions with molecular oxygen during pyrrhotine leaching in sulfuric acid solutions with the participation of nitrous acid as an activator was studied. The oxidation of Fe2+ to Fe3+ only occurr
Iron(II) sulfate oxidation with oxygen on a Pt/C catalyst: A kinetic study
Okhlopkova,Kuznetsova
, p. 34 - 42 (2008)
The kinetics of iron(II) sulfate oxidation with molecular oxygen on the 2% Pt/Sibunit catalyst was studied by a volumetric method at atmospheric pressure, T = 303 K, pH 0.33-2.4, [FeSO4] = 0.06-0.48 mol/l, and [Fe 2(SO4)3] = 0-0.36 mol/l in the absence of diffusion limitations. Relationships were established between the reaction rate and the concentrations of Fe2+, Fe3+, H+, and Cl- ions in the reaction solution. The kinetic isotope effect caused by the replacement of H2O with D2O and of H+ with D+ was measured. The dependence of Fe2+ and Fe 3+ adsorption on the catalyst pretreatment conditions was studied. A reaction scheme is suggested, which includes oxygen adsorption, the formation of a Fe(II) complex with surface oxygen, and the one-electron reduction of oxygen. The last step can proceed via two pathways, namely, electron transfer with H+ addition and hydrogen atom transfer from the coordination sphere of the iron(II) aqua complex. A kinetic equation providing a satisfactory fit to experimental data is set up. Numerical values are determined for the rate constants of the individual steps of the scheme suggested.
Modeling the anodic half-cell of a low-temperature coal fuel cell
Weibel, Douglas B.,Boulatov, Roman,Lee, Andrew,Ferrigno, Rosaria,Whitesides, George M.
, p. 5682 - 5686 (2005)
(Graph Presented) Mined over matter: The partial oxidation of sub-bituminous coal by FeIII ions in 5 M H2SO4 at 100°C was used in the anodic compartment in a prototype coal fuel cell, with a solution of VO2+/VO2+ in 5 M H 2SO4 in the cathodic compartment (see scheme). The cell operated without loss of performance for 1000 h at 100°C, with a maximum current density of 5 A L-1 and a power density of 0.6 W L -1.
