The highly homologous proteins of Fe-containing superoxide dismutase (FeSOD) and MnSOD from Escherichia coli nonetheless exert very different redox tuning on the active site metal ion [Vance; Miller J. Am. Chem. Soc. 1998, 120, 461-467; Biochemistry 2001, 40, 13079-13087]. This was proposed to stem from different hydrogen bonding between the protein and the metal ion's coordinated solvent molec...

Spectroelectrochemical sensing a metal in two different oxidation states, both of which are weakly absorbing in the visible wavelength range, was demonstrated with ferrous and ferric ion. The sensor consisted of an indium tin oxide optically transparent electrode (ITO OTE) coated with a thin film of Nafion preloaded with the ligand 2,2'-bipyridine (bipy). Fe2+ in the sample partitioned into the...

UNLABELLED BACKGROUND The mitochondrial DNA (mtDNA) lies in close proximity to the free radical-producing electron transport chain, thus, it is highly prone to oxidative damage. Oxyphilic type of follicular thyroid carcinoma consists of cells filled - almost exclusively - with aberrant mitochondria. In turn, bivalent iron (Fe2+) and hydrogen peroxide (H2O2) are indispensable for thyroid horm...

We report herein a fluoroionophore sensor derivated from tryptophan that shows high sensitivity (detection limit up to 0.15 microM) and specific selectivity for lead ion (Pb2+) over Ca2+, Cd2+, Co2+, Cr3+, Cu2+, K+, Mg2+, Na+, Fe2+, Mn2+, Ni2+ and Zn2+ in aqueous solution.

The divalent metal-isocitrate site of pig heart NADP-specific isocitrate dehydrogenase can be located by affinity cleavage of the enzyme by Fe(2+)-isocitrate in the presence of O2, in analogy to the "chemical nuclease" action of DNA-binding drugs linked to Fe-EDTA. The enzyme is irreversibly inactivated and cleaved by Fe(2+)-isocitrate more rapidly than by Fe2+. Mn2+ prevents inactivation and c...

A new type of sulfite oxidase which utilizes ferric ion (Fe3+) as an electron acceptor was found in iron-grown Thiobacillus ferrooxidans. It was localized in the plasma membrane of the bacterium and had a pH optimum at 6.0. Under aerobic conditions, 1 mol of sulfite was oxidized by the enzyme to produce 1 mol of sulfate. Under anaerobic conditions in the presence of Fe3+, sulfite was oxidized b...

We have compared the magnetic resonance properties and pH dependence of wild-type and mutant Fe-containing superoxide dismutase (Fe-SOD) in which the conserved active site tyrosine (Tyr 34) is replaced by phenylalanine. The EPR spectrum of the oxidized state and the NMR spectrum of the paramagnetically shifted resonances of the reduced state indicate that in both states the active site is relat...

Abstract: In this paper, kinetics of reductive leaching of manganese dioxide ore by ferrous ion in sulfuric acid media has been examined. Experimental results show that increasing temperature from 20 to 60 °C and decreasing ore particle size from −16+20 to −60+100 mesh considerably enhance both the dissolution rate and efficiency. Molar ratios of Fe2+/MnO2 and H2SO4/MnO2 in excess to the st...

Using UV-VIS spectrophotometric method, the formation constant for interaction of Fe2+(aq) ion with L-Alaninewas experimentally studied at pH = 4.1 ± 0.01 (50mM of potassium hydrogen phthalate buffer), ionic strengthof 0.1M potassium nitrate and at 5 different temperatures 15,20, 25,30 and 35 T. The optical absorption spectraof mixtures containing considered cation and L-Alanine were analyzed b...

BACKGROUND In soils and sediments, manganese oxides and oxygen usually participate in the oxidation of ferrous ions. There is limited information concerning the interaction process and mechanisms of ferrous ions and manganese oxides. The influence of air (oxygen) on reaction process and kinetics has been seldom studied. Because redox reactions usually occur in open systems, the participation of...