Biomaterial Database

Spin trapping study on the kinetics of Fe2+ autoxidation: formation of spin adducts and their destruction by superoxide. 1992

H Kosaka, and Y Katsuki, and T Shiga

Department of Physiology, Medical School, Osaka University, Japan.

The oxidation of Fe2+ was investigated by electron spin resonance spin trapping techniques with N-t-butyl-alpha-phenylnitrone (PBN) and dimethyl sulfoxide. Under pure oxygen, the spin adduct PBN/.OCH3 was rapidly generated by the addition of Fe2+ (0.2-1.2 mM) into phosphate buffer containing ethylenediaminetetraacetate (EDTA), dimethyl sulfoxide, and PBN at pH 7.4, but it decayed. The decay process of PBN/.OCH3 consists of two components. The fast decay was dependent on Fe2+ concentration. Another was due to destruction of the spin adduct by superoxide anion (.O2-), because superoxide dismutase (SOD) markedly prevented the decay. Catalase decreased the yield of PBN/.OCH3. When EDTA was replaced by diethylenetriaminepentaacetic acid (DTPA), both the generation and decay process of PBN/.OCH3 were slow. SOD and catalase effects were similar to those in EDTA. Fe2+ produced PBN/.OCH3 even in the absence of chelators. We could estimate the kinetic parameters by computer simulation, comparing the Fe2+ oxidation in EDTA with that in DTPA. These results demonstrate that Fe2+ reacts with O2 to generate .O2- and then H2O2, which produces .CH3 by reaction with Fe2+ and dimethyl sulfoxide.(.)OCH3 results from the reaction between .CH3 and O2. The adduct PBN/.OCH3 decays by reaction with Fe2+ and .O2-.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009589	Nitrogen Oxides	Inorganic oxides that contain nitrogen.	Nitrogen Oxide,Oxide, Nitrogen,Oxides, Nitrogen
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D003497	Cyclic N-Oxides	Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.	Heterocyclic N-Oxides,Cyclic N Oxides,Heterocyclic N Oxides,N Oxides, Cyclic,N-Oxides, Cyclic,N-Oxides, Heterocyclic,Oxides, Cyclic N
D004369	Pentetic Acid	An iron chelating agent with properties like EDETIC ACID. DTPA has also been used as a chelator for other metals, such as plutonium.	DTPA,Diethylenetriamine Pentaacetic Acid,Pentetates,Penthanil,Ca-DTPA,CaDTPA,CaNa-DTPA,Calcium Trisodium Pentetate,DETAPAC,Indium-DTPA,Mn-Dtpa,Pentacin,Pentacine,Pentaind,Pentetate Calcium Trisodium,Pentetate Zinc Trisodium,Sn-DTPA,Zinc-DTPA,Indium DTPA,Pentaacetic Acid, Diethylenetriamine,Pentetate, Calcium Trisodium,Zinc DTPA
D004492	Edetic Acid	A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.	EDTA,Edathamil,Edetates,Ethylenediaminetetraacetic Acid,Tetracemate,Calcium Disodium Edetate,Calcium Disodium Versenate,Calcium Tetacine,Chelaton 3,Chromium EDTA,Copper EDTA,Coprin,Dicobalt EDTA,Disodium Calcitetracemate,Disodium EDTA,Disodium Ethylene Dinitrilotetraacetate,Distannous EDTA,Edetate Disodium Calcium,Edetic Acid, Calcium Salt,Edetic Acid, Calcium, Sodium Salt,Edetic Acid, Chromium Salt,Edetic Acid, Dipotassium Salt,Edetic Acid, Disodium Salt,Edetic Acid, Disodium Salt, Dihydrate,Edetic Acid, Disodium, Magnesium Salt,Edetic Acid, Disodium, Monopotassium Salt,Edetic Acid, Magnesium Salt,Edetic Acid, Monopotassium Salt,Edetic Acid, Monosodium Salt,Edetic Acid, Potassium Salt,Edetic Acid, Sodium Salt,Ethylene Dinitrilotetraacetate,Ethylenedinitrilotetraacetic Acid,Gallium EDTA,Magnesium Disodium EDTA,N,N'-1,2-Ethanediylbis(N-(carboxymethyl)glycine),Potassium EDTA,Stannous EDTA,Versenate,Versene,Acid, Edetic,Acid, Ethylenediaminetetraacetic,Acid, Ethylenedinitrilotetraacetic,Calcitetracemate, Disodium,Dinitrilotetraacetate, Disodium Ethylene,Dinitrilotetraacetate, Ethylene,Disodium Versenate, Calcium,EDTA, Chromium,EDTA, Copper,EDTA, Dicobalt,EDTA, Disodium,EDTA, Distannous,EDTA, Gallium,EDTA, Magnesium Disodium,EDTA, Potassium,EDTA, Stannous,Edetate, Calcium Disodium,Ethylene Dinitrilotetraacetate, Disodium,Tetacine, Calcium,Versenate, Calcium Disodium
D004578	Electron Spin Resonance Spectroscopy	A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D005296	Ferrous Compounds	Inorganic or organic compounds that contain divalent iron.	Compounds, Ferrous