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Dovrat G, Pevzner S, Maimon E, Bogoslavsky B, Ben-Eliyahu Y, Moisy P, Bettelheim A, Zilbermann I. Macrocyclic Ligand Coordinating Amide-Arm Hydrolysis Reaction Activation in Aqueous Solutions: Tetravalent Uranium Does It Better. Inorg Chem 2024; 63:400-415. [PMID: 38150742 DOI: 10.1021/acs.inorgchem.3c03286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Chelation of lanthanide and actinide cations within a suitable macrocyclic ligand often results in a rigid, kinetically inert, and thermodynamically stable complex. A benchmark for such cation-ligand suitability are cyclen-derived macrocyclic ligands, frequently used as large cation hosts for various applications. Herein, a comprehensive study of the 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane ligand (DOTAM) chelates of UIV and CeIII and their properties in aqueous solutions is presented. By employing multiple analysis techniques, including X-ray crystallography, UV-vis absorbance, 1H NMR, UPLC-MS, cyclic voltammetry, and differential pulse voltammetry, the study has revealed that the two aqueous complexes undergo a spontaneous, gradual, and stepwise hydrolysis of each of the coordinated amides toward carboxylates. The coordination of UIV in the studied reaction has been shown to significantly enhance the reaction rate, leading to an acceleration of up to 6 orders of magnitude compared to the natural process of simple aqueous amides at room temperature. An attempt to describe the unusual chelated metal cation amide-activation feature, based on the relatively lower rigidity of the complex structure, is presented. Additionally, the electrochemical properties of the complex series are discussed in detail, along with the limitations of the analytical methods employed.
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Affiliation(s)
- Gev Dovrat
- Energy Engineering Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Svetlana Pevzner
- Chemistry Department, Nuclear Research Centre Negev, Beer Sheva 84190, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer Sheva 84190, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Benny Bogoslavsky
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | | | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ, Marcoule, Bagnols-sur-cèze 30200, France
| | - Armand Bettelheim
- Chemical Engineering Department, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer Sheva 84190, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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2
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Dovrat G, Pevzner S, Maimon E, Vainer R, Iliashevsky O, Ben‐Eliyahu Y, Moisy P, Bettelheim A, Zilbermann I. Cover Feature: DOTP versus DOTA as Ligands for Lanthanide Cations: Novel Structurally Characterized Ce
IV
and Ce
III
Cyclen‐Based Complexes and Clusters in Aqueous Solutions (Chem. Eur. J. 61/2022). Chemistry 2022. [DOI: 10.1002/chem.202203208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gev Dovrat
- Energy Engineering Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
| | - Svetlana Pevzner
- Chemistry Department Nuclear Research Centre Negev 84190 Beer Sheva Israel
| | - Eric Maimon
- Chemistry Department Nuclear Research Centre Negev 84190 Beer Sheva Israel
- Chemistry Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
| | - Radion Vainer
- Chemistry Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
| | - Olga Iliashevsky
- Chemistry Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
| | | | - Philippe Moisy
- CEA DES ISEC DMRC Univ Montpellier 30207 Bagnols sur Cèze France
| | - Armand Bettelheim
- Chemical Engineering Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
| | - Israel Zilbermann
- Chemistry Department Nuclear Research Centre Negev 84190 Beer Sheva Israel
- Chemistry Department Ben-Gurion University of the Negev Beer-Sheva 84105 Beer Sheva Israel
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3
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Dovrat G, Pevzner S, Maimon E, Vainer R, Iliashevsky O, Ben-Eliyahu Y, Moisy P, Bettelheim A, Zilbermann I. DOTP versus DOTA as ligands for lanthanide cations: Novel structurally characterized Ce(IV) and Ce(III) cyclen‐based complexes and clusters in aqueous solutions. Chemistry 2022; 28:e202201868. [DOI: 10.1002/chem.202201868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Gev Dovrat
- Ben-Gurion University of the Negev Energy Engineering ISRAEL
| | | | - Eric Maimon
- Nuclear Research Centre Negev Chemistry ISRAEL
| | | | | | | | - Philippe Moisy
- CEA Marcoule: Commissariat a l'Energie Atomique et aux Energies Alternatives Marcoule Actinide Chemistry FRANCE
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4
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Lerner A, Meyerstein D, Blahman A, Saphier M, Yardeni G, Maimon E, Kornweitz H, Zilbermann I. On the reactions of Cu(II/I)ATP complexes with methyl radicals. J Inorg Biochem 2022; 234:111883. [PMID: 35717883 DOI: 10.1016/j.jinorgbio.2022.111883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/12/2022] [Accepted: 05/29/2022] [Indexed: 10/18/2022]
Abstract
The CuI/IIATP react with methyl radicals to form methane and methanol, where CuIATP reacts with •CH3 in a process that is surprisingly slow. The low-rate constant of this process is attributed to the significant rearrangement of the chelating ligand required for the transient's formation. These results were corroborated by DFT calculations of the relevant compounds.
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Affiliation(s)
- Ana Lerner
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Israel Atomic Energy Commission, Tel Aviv, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Department of Chemical Sciences, The Radical Research Center and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Application, Ariel University, Ariel, Israel.
| | - Alex Blahman
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Israel Atomic Energy Commission, Tel Aviv, Israel
| | - Magal Saphier
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Haya Kornweitz
- Department of Chemical Sciences, The Radical Research Center and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Application, Ariel University, Ariel, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel.
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5
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Avraham E, Meyerstein D, Lerner A, Yardeni G, Pevzner S, Zilbermann I, Moisy P, Maimon E, Popivker I. Reactions of methyl, hydroxyl and peroxyl radicals with the DOTA chelating agent used in medical imaging. Free Radic Biol Med 2022; 180:134-142. [PMID: 34973364 DOI: 10.1016/j.freeradbiomed.2021.12.313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/13/2021] [Accepted: 12/27/2021] [Indexed: 12/30/2022]
Abstract
The mechanism of reaction of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) with ·CH3, CH3O2· and ·OH radicals were studied. The radicals were formed in situ radiolytically. The methyl radicals react orders of magnitude slower with DOTA and with MIII(DOTA)- than the hydroxyl radicals. The various final products were identified and mechanisms for their formation are proposed. CH3O2· radicals do not react, or react too slowly to be observed, with DOTA and with MIII(DOTA)- as long as the central cation is not oxidized by the peroxyl radical. The results imply that synthesis of the MIII(DOTA)-(MIII = radioisotope) complexes in a water-organic solvent (ethanol or 2-propanol or acetonitrile) mixture is not only kinetically desired but the so formed complex also decreases the radiolytic decomposition of DOTA.
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Affiliation(s)
- Elad Avraham
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Department of Chemical Sciences, The Radical Research Center and the Schlesinger Family, Center for Compact Accelerators, Radiation Sources and Application, Ariel University, Ariel, Israel; Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ana Lerner
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Israel Atomic Energy Commission, Tel Aviv, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Svetlana Pevzner
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Eric Maimon
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Inna Popivker
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel.
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6
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Dovrat G, Pevzner S, Berthon C, Lerner A, Maimon E, Vainer R, Karpasas M, Ben-Elyiahu Y, Moisy P, Bettelheim A, Zilbermann I. Oligomers Intermediates in Between Two New Distinct Homonuclear Uranium(IV) DOTP Complexes*. Chemistry 2021; 27:8264-8267. [PMID: 33822408 DOI: 10.1002/chem.202005350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Indexed: 12/19/2022]
Abstract
Two new aqueous UIV complexes were synthesized by the interaction between the tetravalent uranium cation and the (1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetra(methylene phosphonic acid) (DOTP) macrocyclic ligand. Two distinct homonuclear complexes were identified; the first was characterized by X-ray crystallography as a unique "out-of-cage", [U(DOTPH6 )2 ] complex, in which the UIV cation is octa-coordinated to 4 phosphonic arms from each ligand in a square anti-prism geometry, with a C4 symmetry. The second is the "in-cage" [U(DOTPH4 )] complex, in which the tetravalent cation is located between the macrocycle O4 and N4 planes. With the help of UV-Vis absorption, 1 H/31 P NMR, ATR-IR, and MALDI-TOFMS analytical techniques, the chemical interchange between both species is presented. It is shown that the one-way transition is governed by the formation of a multiple number of soluble oligomeric species consisting of varied stoichiometric ratios of both characterized homonuclear complexes.
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Affiliation(s)
- Gev Dovrat
- Energy Engineering Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | - Svetlana Pevzner
- Chemistry Department, Nuclear Research Centre Negev, IL-84190, Beer-Sheva, Israel
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Ana Lerner
- Israeli Atomic Energy Commission, Tel-Aviv, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, IL-84190, Beer-Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | - Radion Vainer
- Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | - Mark Karpasas
- Research Support Laboratories, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | | | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Armand Bettelheim
- Chemical Engineering Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, IL-84190, Beer-Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, Beer-Sheva, 84105, Israel
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7
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Popivker I, Meyerstein D, Gitin D, Avraham EN, Maimon E, Zidki T, Cohen H, Yardeni G, Moisy P, Pevzner S, Zilbermann I. Redox Properties of Ce IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study. J Phys Chem A 2021; 125:1436-1446. [PMID: 33566599 DOI: 10.1021/acs.jpca.0c09134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The redox chemistry of CeIIIDOTA in cage in carbonate solutions was studied using electrochemistry and radiolysis techniques (continuous radiolysis and pulse radiolysis). Spectroscopic measurements point out that the species present in the solutions at high bicarbonate concentrations are [CeIIIDOTA(CO3)]3- (or less plausible [CeIIIDOTA(HCO3)]2-) with the carbonate (bicarbonate) anion as the ninth ligand versus [CeIIIDOTA(H2O)]- present in the absence of bicarbonate. Electrochemical results show a relatively low increase in the thermodynamic stabilization of the redox couple CeIV/III in the presence of carbonate versus its aqueous analogue. [CeIVDOTA(CO3)]2- and [CeIVDOTA(H2O)], prepared electrochemically, decompose photolytically. However, kept in the dark, both are relatively long lived; [CeIVDOTA(H2O)], though, is orders of magnitude kinetically more stable (a considerably longer half-life). Thus, one concludes that the carbonate species have a different mechanism of decomposition depending also on the presence of dioxygen after its preparation (in deaerated/aerated solutions). The [CeIVDOTA(CO3)]2- species is produced radiolytically by oxidation of the trivalent species by CO3•- with a rate constant, measured using pulse radiolysis, of 3.3 × 105 M-1 s-1. This rate constant is at least 1 order of magnitude smaller than most of the rate constants so far reported for the reaction of CO3•- with transition metal/lanthanide (cerium)/actinide complexes. This result together with the bulkiness of the reactants might suggest an outer-sphere electron transfer rather than the inner-sphere one so far proposed. The lifetime of the tetravalent cerium species obtained radiolytically in the presence of carbonate is shorter than the electrochemical one, suggesting a different conformer involved.
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Affiliation(s)
- Inna Popivker
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel
| | - Dan Meyerstein
- Department of Chemical Sciences and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel 40700, Israel.,Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
| | - Dalia Gitin
- Department of Chemical Sciences and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel 40700, Israel
| | - Elad N Avraham
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel.,Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel.,Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
| | - Tomer Zidki
- Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
| | - Haim Cohen
- Department of Chemical Sciences and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel 40700, Israel.,Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, University of Montpellier, 30207 Bagnols-sur-Cèze, Marcoule, France
| | - Svetlana Pevzner
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre-Negev, P.O. Box 9001, Beer-Sheva 84190, Israel.,Chemistry Department, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84170, Israel
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8
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Yardeni G, Meyerstein D, Mikhailovich-Jivin E, Kats L, Cohen H, Zilbermann I, Maimon E. The reactions of the Cu(II)-nitrilotris(methylenephosphonic acid) complex with alkyl radicals in aqueous solutions. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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Dovrat G, Illy MC, Berthon C, Lerner A, Mintz MH, Maimon E, Vainer R, Ben-Eliyahu Y, Moiseev Y, Moisy P, Bettelheim A, Zilbermann I. On the Aqueous Chemistry of the U IV -DOTA Complex. Chemistry 2020; 26:3390-3403. [PMID: 31943407 DOI: 10.1002/chem.201905357] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/24/2019] [Indexed: 01/24/2023]
Abstract
The 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) aqueous complex of UIV with H2 O, OH- , and F- as axial ligands was studied by using UV/Vis spectrophotometry, ESI-MS, NMR spectroscopy, X-ray crystallography, and electrochemistry. The UIV -DOTA complex with either water or fluoride as axial ligands was found to be inert to oxidation by molecular oxygen, whereas the complex with hydroxide as an axial ligand slowly hydrolyzed and was oxidized by dioxygen to a diuranate precipitate. The combined data set acquired shows that, although axial substitution of fluoride and hydroxide ligands instead of water does not seem to significantly change the aqueous DOTA complex structure, it has an important effect on the electronic configuration of the complex. The UIV /UIII redox couple was found to be quasi-reversible for the complex with both axially bonded H2 O and hydroxide, but irreversible for the complex with axially bonded fluoride. Intriguingly, binding of the axial fluoride renders the irreversible one-electron UV /UIV oxidation of the [UIV (DOTA)(H2 O)] complex quasi-reversible, which suggests the formation of the short-lived pentavalent form of the complex, an aqueous non-uranyl chelated UV cation.
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Affiliation(s)
- Gev Dovrat
- Nuclear Engineering Department, Ben-Gurion University of the Negev, 84105, Beer-Sheva, Israel
| | | | - Claude Berthon
- CEA, DEN, DMRC, Univ Montpellier, BP17171, 30207, Marcoule, France
| | - Ana Lerner
- Israeli Atomic Energy Commission, 61070, Tel-Aviv, Israel.,Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Moshe H Mintz
- Nuclear Engineering Department, Ben-Gurion University of the Negev, 84105, Beer-Sheva, Israel.,Chemistry Department, Nuclear Research Centre Negev, 84190, Beer Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, 84190, Beer Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Radion Vainer
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | | | - Yulia Moiseev
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Philippe Moisy
- CEA, DEN, DMRC, Univ Montpellier, BP17171, 30207, Marcoule, France
| | - Armand Bettelheim
- Chemical Engineering Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, 84190, Beer Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
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10
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Yardeni G, Meyerstein D, Kats L, Cohen H, Zilbermann I, Maimon E. On the reactions of methyl radicals with nitrilotris(methylenephosphonic-acid) complexes in aqueous solutions. J COORD CHEM 2019. [DOI: 10.1080/00958972.2019.1698736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Chemical Sciences Department, The Radical Research Centre and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Lioubov Kats
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Haim Cohen
- Chemical Sciences Department, The Radical Research Centre and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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11
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Maimon E, Samuni A, Goldstein S. Mechanistic insight into the catalytic inhibition by nitroxides of tyrosine oxidation and nitration. Biochim Biophys Acta Gen Subj 2019; 1863:129403. [PMID: 31356821 DOI: 10.1016/j.bbagen.2019.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/03/2019] [Accepted: 07/24/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Nitroxide antioxidants (RNO•) protect from injuries associated with oxidative stress. Tyrosine residues in proteins are major targets for oxidizing species giving rise to irreversible cross-linking and protein nitration, but the mechanisms underlying the protective activity of RNO• on these processes are not sufficiently clear. METHODS Tyrosine oxidation by the oxoammonium cation (RN+=O) was studied by following the kinetics of RNO• formation using EPR spectroscopy. Tyrosine oxidation and nitration were investigated using the peroxidase/H2O2 system without and with nitrite. The inhibitory effect of RNO• on these processes was studied by following the kinetics of the evolved O2 and accumulation of tyrosine oxidation and nitration products. RESULTS Tyrosine ion is readily oxidized by RN+=O, and the equilibrium constant of this reaction depends on RNO• structure and reduction potential. RNO• catalytically inhibits tyrosine oxidation and nitration since it scavenges both tyrosyl and •NO2 radicals while recycling through RN+=O reduction by H2O2, tyrosine and nitrite. The inhibitory effect of nitroxide on tyrosine oxidation and nitration increases as its reduction potential decreases where the 6-membered ring nitroxides are better catalysts than the 5-membered ones. CONCLUSIONS Nitroxides catalytically inhibit tyrosine oxidation and nitration. The proposed reaction mechanism adequately fits the results explaining the dependence of the nitroxide inhibitory effect on its reduction potential and on the concentrations of the reducing species present in the system. GENERAL SIGNIFICANCE Nitroxides protect against both oxidative and nitrative damage. The proposed reaction mechanism further emphasizes the role of the reducing environment to the efficacy of these catalysts.
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Affiliation(s)
- Eric Maimon
- Nuclear Research Centre Negev and Chemistry Department, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Amram Samuni
- Institute of Medical Research, Israel-Canada Medical School, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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12
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Samuni U, Maimon E, Goldstein S. A kinetic study of the oxidation of hydroxamic acids by compounds I and II of horseradish peroxidase: Effect of transition metal ions. J COORD CHEM 2018. [DOI: 10.1080/00958972.2018.1493200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Uri Samuni
- Chemistry & Biochemistry Department, Queens College, City University of New York, Flushing, NY, USA
- Ph.D. Programs in Biochemistry and Chemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Eric Maimon
- Nuclear Research Centre Negev, Beer Sheva, Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory, the Hebrew University of Jerusalem, Jerusalem, Israel
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13
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Shamir D, Meyerstein D, Zilbermann I, Burg A, Albo Y, Shames AI, Vainer R, Borojovich EJ, Yardeni G, Kornweitz H, Maimon E. Copper(II) catalyses the reduction of perchlorate by both formaldehyde and by dihydrogen in aqueous solutions. J COORD CHEM 2018. [DOI: 10.1080/00958972.2018.1506114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Dror Shamir
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Chemical Sciences Department, Ariel University, Ariel, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ariela Burg
- Chemical Engineering Department, The Sami Shamoon College of Engineering, Beer-Sheva, Israel
| | - Yael Albo
- Department of Chemical Engineering, Biotechnology and Materials, Ariel University, Ariel, Israel
| | | | - Radion Vainer
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Haya Kornweitz
- Chemical Sciences Department, Ariel University, Ariel, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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14
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Affiliation(s)
- Amir Mizrahi
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Haim Cohen
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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15
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Maimon E, Lerner A, Samuni A, Goldstein S. Direct Observation of Acyl Nitroso Compounds in Aqueous Solution and the Kinetics of Their Reactions with Amines, Thiols, and Hydroxamic Acids. J Phys Chem A 2018; 122:7006-7013. [PMID: 30111101 DOI: 10.1021/acs.jpca.8b06672] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acyl nitroso compounds or nitrosocarhonyls (RC(O)N═O) are reactive short-lived electrophiles, and their hydrolysis and reactions with nucleophiles produce HNO. Previously, direct detection of acyl nitroso species in nonaqueous media has been provided by time-resolved infrared spectroscopy demonstrating that its half-life is about 1 ms. In the present study hydroxamic acids (RC(O)NHOH) are oxidized electrochemically in buffered aqueous solutions (pH 5.9-10.2) yielding transient species characterized by their maximal absorption at 314-330 nm. These transient species decompose via a first-order reaction yielding mainly HNO and the respective carboxylic acid and therefore are ascribed to RC(O)N═O. The sufficiently long half-life of RC(O)N═O in aqueous solution allows for the first time the study of the kinetics of its reactions with various nucleophiles demonstrating that the nucleophilic reactivity follows the order thiolate > hydroxamate > amine. Metal chelates of CH3C(O)NHOH catalyze the hydrolysis of CH3C(O)N═O at the efficacy order of CuII > ZnII > NiII > CoII where only CuII catalyzes the hydrolysis also in the absence of the hydroxamate. Finally, oxidation of hydroxamic acids generates HNO, and the rate of this process is determined by the half-life of the respective acyl nitroso compound.
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Affiliation(s)
- Eric Maimon
- Nuclear Research Centre Negev, Beer Sheva 84190 , Israel.,Chemistry Department , Ben-Gurion University , Beer-Sheva 84105 , Israel
| | - Ana Lerner
- Chemistry Department , Ben-Gurion University , Beer-Sheva 84105 , Israel
| | - Amram Samuni
- Institute of Medical Research-Israel Canada, Medical School , The Hebrew University of Jerusalem , Jerusalem 91120 , Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
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16
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Maimon E, Samuni A, Goldstein S. Nitrogen Dioxide Reaction with Nitroxide Radical Derived from Hydroxamic Acids: The Intermediacy of Acyl Nitroso and Nitroxyl (HNO). J Phys Chem A 2018; 122:3747-3753. [PMID: 29608853 DOI: 10.1021/acs.jpca.8b02300] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydroxamic acids (RC(O)NHOH) form a class of compounds that display interesting chemical and biological properties The chemistry of RC(O)NHOH) is associated with one- and two-electron oxidations forming the respective nitroxide radical (RC(O)NHO•) and acyl nitroso (RC(O)N═O), respectively, which are relatively unstable species. In the present study, the kinetics and mechanism of the •NO2 reaction with nitroxide radicals derived from acetohydroxamic acid, suberohydroxamic acid, benzohydroxamic acid, and suberoylanilide hydroxamic acid have been studied in alkaline solutions. Ionizing radiation was used to generate about equal yields of these radicals, demonstrating that the oxidation of the transient nitroxide radical by •NO2 produces HNO and nitrite at about equal yields. The rate constant of •NO2 reaction with the nitroxide radical derived from acetohydroxamic acid has been determined to be (2.5 ± 0.5) × 109 M-1 s-1. This reaction forms a transient intermediate absorbing at 314 nm, which decays via a first-order reaction whose rate increases upon increasing the pH or the hydroxamic acid concentration. Transient intermediates absorbing around 314 nm are also formed during the oxidation of hydroxamic acids by H2O2 catalyzed by horseradish peroxidase. It is shown that HNO is formed during the decomposition of these intermediates, and therefore, they are assigned to acyl nitroso compounds. This study provides for the first time a direct spectrophotometric detection of acyl nitroso compounds in aqueous solutions allowing the study of their chemistry and reaction kinetics.
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Affiliation(s)
- Eric Maimon
- Nuclear Research Centre Negev , Beer Sheva , Israel
| | - Amram Samuni
- Institute of Medical Research Israel-Canada , Medical School, The Hebrew University of Jerusalem , Jerusalem 91120 , Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
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17
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Mizrahi A, Maimon E, Cohen H, Kornweitz H, Zilbermann I, Meyerstein D. Cover Feature: Mechanistic Studies on the Role of [Cu II
(CO 3
)
n
] 2−2n
as a Water Oxidation Catalyst: Carbonate as a Non-Innocent Ligand (Chem. Eur. J. 5/2018). Chemistry 2018. [DOI: 10.1002/chem.201704981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Amir Mizrahi
- Chemistry Department; Nuclear Research Centre Negev Beer-Sheva; Israel
| | - Eric Maimon
- Chemistry Department; Nuclear Research Centre Negev Beer-Sheva; Israel
- Chemistry Department; Ben-Gurion University of the Negev Beer-Sheva; 84105 Israel
| | - Haim Cohen
- Chemical Sciences Department and the Schlesinger Family Center for, Compact Accelerators Radiation Sources and Applications; Ariel University, Ariel; Israel
| | - Haya Kornweitz
- Chemical Sciences Department; Ariel University; Ariel Israel
| | - Israel Zilbermann
- Chemistry Department; Nuclear Research Centre Negev Beer-Sheva; Israel
- Chemistry Department; Ben-Gurion University of the Negev Beer-Sheva; 84105 Israel
| | - Dan Meyerstein
- Chemical Sciences Department and the Schlesinger Family Center for, Compact Accelerators Radiation Sources and Applications; Ariel University, Ariel; Israel
- Chemistry Department; Ben-Gurion University of the Negev Beer-Sheva; 84105 Israel
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18
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Mizrahi A, Maimon E, Cohen H, Kornweitz H, Zilbermann I, Meyerstein D. Mechanistic Studies on the Role of [Cu II (CO 3 ) n ] 2-2n as a Water Oxidation Catalyst: Carbonate as a Non-Innocent Ligand. Chemistry 2017; 24:1088-1096. [PMID: 28921692 DOI: 10.1002/chem.201703742] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Indexed: 11/05/2022]
Abstract
Recently it was reported that copper bicarbonate/carbonate complexes are good electro-catalysts for water oxidation. However, the results did not enable a decision whether the active oxidant is a CuIII or a CuIV complex. Kinetic analysis of pulse radiolysis measurements coupled with DFT calculations point out that CuIII (CO3 )n3-2n complexes are the active intermediates in the electrolysis of CuII (CO3 )n2-2n solution. The results enable the evaluation of E°[(CuIII/II (CO3 )n )aq ]≈1.42 V versus NHE at pH 8.4. This redox potential is in accord with the electrochemical report. As opposed to literature suggestions for water oxidation, the present results rule out single-electron transfer from CuIII (CO3 )n3-2n to yield hydroxyl radicals. Significant charge transfer from the coordinated carbonate to CuIII results in the formation of C2 O62- by means of a second-order reaction of CuIII (CO3 )n3-2n . The results point out that carbonate stabilizes transition-metal cations at high oxidation states, not only as a good sigma donor, but also as a non-innocent ligand.
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Affiliation(s)
- Amir Mizrahi
- Chemistry Department, Nuclear Research Centre Negev Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev Beer-Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, 84105, Israel
| | - Haim Cohen
- Chemical Sciences Department and the Schlesinger Family Center for, Compact Accelerators Radiation Sources and Applications, Ariel University, Ariel, Israel
| | - Haya Kornweitz
- Chemical Sciences Department, Ariel University, Ariel, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev Beer-Sheva, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, 84105, Israel
| | - Dan Meyerstein
- Chemical Sciences Department and the Schlesinger Family Center for, Compact Accelerators Radiation Sources and Applications, Ariel University, Ariel, Israel.,Chemistry Department, Ben-Gurion University of the Negev Beer-Sheva, 84105, Israel
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19
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Samuni A, Maimon E, Goldstein S. Mechanism of HRP-catalyzed nitrite oxidation by H 2O 2 revisited: Effect of nitroxides on enzyme inactivation and its catalytic activity. Free Radic Biol Med 2017; 108:832-839. [PMID: 28495446 DOI: 10.1016/j.freeradbiomed.2017.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/01/2017] [Accepted: 05/07/2017] [Indexed: 10/19/2022]
Abstract
The peroxidative activity of horseradish peroxidase (HRP) undergoes progressive inactivation while catalyzing the oxidation of nitrite by H2O2. The extent of inactivation increases as the pH increases, [nitrite] decreases or [H2O2] increases, and is accompanied by a loss of the Soret peak of HRP along with yellow-greenish coloration of the solution. HRP-catalyzed nitrite oxidation by H2O2 involves not only the formation of compounds I and II as transient heme species, but also compound III, all of which in turn, oxidize nitrite yielding •NO2. The rate constant of nitrite oxidation by compound III is at least 10-fold higher than that by compound II, which is also reducible by •NO2 where its reduction by nitrite is the rate-determining step of the catalytic cycle. The extent of the loss of the Soret peak of HRP is lower than the loss of its peroxidative activity implying that deterioration of the heme moiety leading to iron release only partially contributes toward heme inactivation. Cyclic stable nitroxide radicals, such as 2,2,6,6-tetramethyl-piperidine-N-oxyl (TPO), 4-OH-TPO and 4-NH2-TPO at µM concentrations detoxify •NO2 thus protecting HRP against inactivation mediated by this radical. Hence, HRP inactivation proceeds via nitration of the porphyrin ring most probably through compound I reaction with •NO2, which partially leads to deterioration of the heme moiety. The nitroxide acts catalytically since its oxidation by •NO2 yields the respective oxoammonium cation, which is readily reduced back to the nitroxide by H2O2, superoxide ion radical, and nitrite. In addition, the nitroxide catalytically inhibits tyrosine nitration mediated by HRP/H2O2/nitrite reactions system as it efficiently competes with tyrosyl radical for •NO2. The inhibition by nitroxides of tyrosine nitration is demonstrated also in the case of microperoxidase (MP-11) and cytochrome c revealing an additional role played by nitroxide antioxidants.
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Affiliation(s)
- Amram Samuni
- Institute of Medical Research Israel-Canada, Medical School, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Eric Maimon
- Nuclear Research Centre Negev, Be'er Sheva, Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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20
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Samuni A, Maimon E, Goldstein S. Nitroxides protect horseradish peroxidase from H 2O 2-induced inactivation and modulate its catalase-like activity. Biochim Biophys Acta Gen Subj 2017; 1861:2060-2069. [PMID: 28365302 DOI: 10.1016/j.bbagen.2017.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/05/2017] [Accepted: 03/20/2017] [Indexed: 11/24/2022]
Abstract
BACKGROUND Horseradish peroxidase (HRP) catalyzes H2O2 dismutation while undergoing heme inactivation. The mechanism underlying this process has not been fully elucidated. The effects of nitroxides, which protect metmyoglobin and methemoglobin against H2O2-induced inactivation, have been investigated. METHODS HRP reaction with H2O2 was studied by following H2O2 depletion, O2 evolution and heme spectral changes. Nitroxide concentration was followed by EPR spectroscopy, and its reactions with the oxidized heme species were studied using stopped-flow. RESULTS Nitroxide protects HRP against H2O2-induced inactivation. The rate of H2O2 dismutation in the presence of nitroxide obeys zero-order kinetics and increases as [nitroxide] increases. Nitroxide acts catalytically since its oxidized form is readily reduced to the nitroxide mainly by H2O2. The nitroxide efficacy follows the order 2,2,6,6-tetramethyl-piperidine-N-oxyl (TPO)>4-OH-TPO>3-carbamoyl proxyl>4-oxo-TPO, which correlates with the order of the rate constants of nitroxide reactions with compounds I, II, and III. CONCLUSIONS Nitroxide catalytically protects HRP against inactivation induced by H2O2 while modulating its catalase-like activity. The protective role of nitroxide at μM concentrations is attributed to its efficient oxidation by P940, which is the precursor of the inactivated form P670. Modeling the dismutation kinetics in the presence of nitroxide adequately fits the experimental data. In the absence of nitroxide the simulation fits the observed kinetics only if it does not include the formation of a Michaelis-Menten complex. GENERAL SIGNIFICANCE Nitroxides catalytically protect heme proteins against inactivation induced by H2O2 revealing an additional role played by nitroxide antioxidants in vivo.
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Affiliation(s)
- Amram Samuni
- Institute of Medical Research Israel-Canada, Medical School, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Eric Maimon
- Nuclear Research Centre Negev, Beer Sheva, Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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21
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Samuni A, Maimon E, Goldstein S. Nitroxides catalytically inhibit nitrite oxidation and heme inactivation induced by H 2O 2, nitrite and metmyoglobin or methemoglobin. Free Radic Biol Med 2016; 101:491-499. [PMID: 27826125 DOI: 10.1016/j.freeradbiomed.2016.10.534] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/22/2016] [Accepted: 10/25/2016] [Indexed: 11/18/2022]
Abstract
Stable nitroxide radicals have multiple biological effects, although the mechanisms underlying them are not fully understood. Their protective effect against oxidative damage has been mainly attributed to scavenging deleterious radicals, oxidizing reduced metal ions and reducing oxyferryl centers of heme proteins. Yet, the potential of nitroxides to protect heme proteins against inactivation while suppressing or enhancing their catalytic activities has been largely overlooked. We have studied the effect of nitroxides, including TPO (2,2,6,6-tetramethylpiperidin-N-oxyl), 4-OH-TPO, 4-oxo-TPO and 3-carbamoyl proxyl, on the peroxidase-like activity of metmyoglobin (MbFeIII) and methemoglobin (HbFeIII) using nitrite as an electron donor by following heme absorption, H2O2 consumption, O2 evolution and nitrite oxidation. The results demonstrate that the peroxidase-like activity is accompanied by a progressive heme inactivation where MbFeIII is far more resistant than HbFeIII. Nitroxides convert the peroxidase-like activity into catalase-like activity while inhibiting heme inactivation and nitrite oxidation in a dose-dependent manner. The nitroxide facilitates H2O2 dismutation, yet none of its reactions with any of the intermediates formed in these systems is rate-determining, and therefore its effect on the rate of the catalysis is hardly dependent on the kind of the nitroxide derivative and its concentration. The nitroxide at µM concentrations range catalytically inhibits nitrite oxidation, and consequently prevents tyrosine nitration induced by heme protein/H2O2/nitrite due to its fast oxidation by •NO2 forming the respective oxoammonium cation, which is reduced back to the nitroxide by H2O2 and by superoxide radical. The nitroxides are superior over common antioxidants, which their reaction with •NO2 always yields secondary radicals leading eventually to consumption of the antioxidant. A mechanism is proposed, and the kinetic simulations fit very well the experimental data in the case of MbFeIII where most of the rate constants of the reactions involved are independently known.
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Affiliation(s)
- Amram Samuni
- Institute of Medical Research, Israel-Canada Medical School, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Eric Maimon
- Nuclear Research Centre Negev, Beer Sheva, Israel
| | - Sara Goldstein
- Institute of Chemistry, The Accelerator Laboratory, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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22
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Affiliation(s)
- Amir Mizrahi
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Haim Cohen
- Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
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23
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Yanus RL, Yardeni G, Maimon E, Saphier M, Zilbermann I, Meyerstein D. BH
4
–
‐Promoted, Radical‐Initiated, Catalytic Oxidation of (CH
3
)
2
SO by N
2
O in Aqueous Solution. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Rinat Levy Yanus
- Chemistry Department, Nuclear Research Centre Negev, P.O.B. 9001, 8419001 Beer Sheva, Israel
- Chemistry Department, Ben‐Gurion University of the Negev, P.O.B. 653, 8410501 Beer Sheva, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, P.O.B. 9001, 8419001 Beer Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, P.O.B. 9001, 8419001 Beer Sheva, Israel
- Chemistry Department, Ben‐Gurion University of the Negev, P.O.B. 653, 8410501 Beer Sheva, Israel
| | - Magal Saphier
- Chemistry Department, Nuclear Research Centre Negev, P.O.B. 9001, 8419001 Beer Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, P.O.B. 9001, 8419001 Beer Sheva, Israel
- Chemistry Department, Ben‐Gurion University of the Negev, P.O.B. 653, 8410501 Beer Sheva, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben‐Gurion University of the Negev, P.O.B. 653, 8410501 Beer Sheva, Israel
- Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel, http://www.ariel.ac.il/sites/dan‐meyerstein
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24
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Burg A, Shamir D, Apelbaum L, Albo Y, Maimon E, Meyerstein D. Electrocatalytic Oxidation of Amines by Ni(1,4,8,11‐tetraazacyclotetradecane)
2+
Entrapped in Sol–Gel Electrodes. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Burg A, Shamir D, Apelbaum L, Albo Y, Maimon E, Meyerstein D. Electrocatalytic Oxidation of Amines by Ni(1,4,8,11‐tetraazacyclotetradecane)
2+
Entrapped in Sol–Gel Electrodes (Eur. J. Inorg. Chem. 4/2016). Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201690006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ariela Burg
- Chemical Engineering Department, SCE – Shamoon College of Engineering, Beer‐Sheva, Israel
| | - Dror Shamir
- Nuclear Research Centre Negev, P.O.B. 9001, Beer‐Sheva, Israel
| | - Lina Apelbaum
- R & D, Makhteshim Chemical Works, Ltd., Beer Sheva, Israel
| | - Yael Albo
- Chemical Engineering Department, Ariel University, Ariel, Israel
| | - Eric Maimon
- Nuclear Research Centre Negev, P.O.B. 9001, Beer‐Sheva, Israel
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Biological Chemistry Department, Ariel University, Ariel, Israel
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26
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Burg A, Shamir D, Apelbaum L, Albo Y, Maimon E, Meyerstein D. Electrocatalytic Oxidation of Amines by Ni(1,4,8,11‐tetraazacyclotetradecane)
2+
Entrapped in Sol–Gel Electrodes. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500985] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Ariela Burg
- Chemical Engineering Department, SCE – Shamoon College of Engineering, Beer‐Sheva, Israel
| | - Dror Shamir
- Nuclear Research Centre Negev, P.O.B. 9001, Beer‐Sheva, Israel
| | - Lina Apelbaum
- R & D, Makhteshim Chemical Works, Ltd., Beer Sheva, Israel
| | - Yael Albo
- Chemical Engineering Department, Ariel University, Ariel, Israel
| | - Eric Maimon
- Nuclear Research Centre Negev, P.O.B. 9001, Beer‐Sheva, Israel
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Biological Chemistry Department, Ariel University, Ariel, Israel
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27
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Albo Y, Buzaglo N, Maimon E, Zilbermann I, Meyerstein D. Design of a ligand suitable for sensitive uranyl analysis in aqueous solutions. J COORD CHEM 2015. [DOI: 10.1080/00958972.2015.1043287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Yael Albo
- Chemical Engineering Department, Ariel University, Ariel, Israel
| | - Nina Buzaglo
- Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Biological Chemistry Department, Ariel University, Ariel, Israel
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28
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Gifford I, Vreeland W, Grdanovska S, Burgett E, Kalinich J, Vergara V, Wang CKC, Maimon E, Poster D, Al-Sheikhly M. Liposome-based delivery of a boron-containing cholesteryl ester for high-LET particle-induced damage of prostate cancer cells: A boron neutron capture therapy study. Int J Radiat Biol 2014; 90:480-5. [DOI: 10.3109/09553002.2014.901579] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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29
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Schutz O, Masarwa A, Zilbermann I, Maimon E, Cohen H, Meyerstein D. On the Mechanism of Reduction of Maleate Ions by Ni
I
Complexes with Tetraazamacrocyclic Ligands in Aqueous Solutions. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201301115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Osnat Schutz
- Department of Chemistry, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel, http://in.bgu.ac.il/en/Pages/default.aspx
| | - Alexandra Masarwa
- Department of Chemistry, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel, http://in.bgu.ac.il/en/Pages/default.aspx
| | - Israel Zilbermann
- Department of Chemistry, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel, http://in.bgu.ac.il/en/Pages/default.aspx
- Chemistry Department, Nuclear Research Centre Negev, Beer‐Sheva, Israel
| | - Eric Maimon
- Department of Chemistry, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel, http://in.bgu.ac.il/en/Pages/default.aspx
- Chemistry Department, Nuclear Research Centre Negev, Beer‐Sheva, Israel
| | - Haim Cohen
- Department of Biological Chemistry, Ariel University, Ariel, Israel, http://www.ariel.ac.il/en
| | - Dan Meyerstein
- Department of Chemistry, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel, http://in.bgu.ac.il/en/Pages/default.aspx
- Department of Biological Chemistry, Ariel University, Ariel, Israel, http://www.ariel.ac.il/en
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Attia S, Shames A, Zilbermann I, Goobes G, Maimon E, Meyerstein D. Covalent binding of a nickel macrocyclic complex to a silica support: towards an electron exchange column. Dalton Trans 2014; 43:103-10. [DOI: 10.1039/c3dt51962g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yardeni G, Zilbermann I, Maimon E, Kats L, Bar-Ziv R, Meyerstein D. H/D Kinetic Isotope Effect as a Tool to Elucidate the Reaction Mechanism of Methyl Radicals with Glycine in Aqueous Solutions. J Phys Chem A 2013; 117:13996-8. [DOI: 10.1021/jp4090052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Guy Yardeni
- Chemistry
Department, Nuclear Research Centre Negev, Beer-Sheva, 86000, Israel
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Israel Zilbermann
- Chemistry
Department, Nuclear Research Centre Negev, Beer-Sheva, 86000, Israel
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Eric Maimon
- Chemistry
Department, Nuclear Research Centre Negev, Beer-Sheva, 86000, Israel
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Lioubov Kats
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Ronen Bar-Ziv
- Chemistry
Department, Nuclear Research Centre Negev, Beer-Sheva, 86000, Israel
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Dan Meyerstein
- Chemistry
Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
- Biological
Chemistry Department, Ariel University, Ariel, 44837, Israel
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Ittah E, Shamir D, Zilbermann I, Maimon E, Yardeni G, Shames AI, Meyerstein D. Pyrophosphate as a stabilizer of Ni(III) ions in aqueous solutions. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Popivker I, Zilbermann I, Maimon E, Cohen H, Meyerstein D. The “Fenton like” reaction of MoO43− involves two H2O2 molecules. Dalton Trans 2013; 42:16666-8. [DOI: 10.1039/c3dt52333k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zilbermann I, Meron E, Maimon E, Soifer L, Elbaz L, Korin E, Bettelheim A. Tautomerism in N-confused porphyrins as the basis of a novel fiber-optic humidity sensor. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424606000089] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is shown that N -confused porphyrins exhibit tautomerism not only in organic solvents, as already reported, but also after incorporation in dry/humid Nafion films. This allows the development of a new fiber-optic humidity sensor which exhibits long-term stability and a linear response over the humidity range 0 to at least 4000 ppm.
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Affiliation(s)
- Israel Zilbermann
- Nuclear Research Centre-Negev, P.O.Box 9001, Beer-Sheva 84190, Israel
| | - Eli Meron
- Nuclear Research Centre-Negev, P.O.Box 9001, Beer-Sheva 84190, Israel
| | - Eric Maimon
- Nuclear Research Centre-Negev, P.O.Box 9001, Beer-Sheva 84190, Israel
| | - Leonid Soifer
- Chemical Engineering Department, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva 84105, Israel
| | - Lior Elbaz
- Chemical Engineering Department, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva 84105, Israel
| | - Eli Korin
- Chemical Engineering Department, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva 84105, Israel
| | - Armand Bettelheim
- Chemical Engineering Department, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva 84105, Israel
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Popivker I, Zilbermann I, Maimon E, Cohen H, Meyerstein D. The one-electron reduction of a multi-centred iron(III) polyoxometallate. A pulse radiolysis study. INORG CHEM COMMUN 2011. [DOI: 10.1016/j.inoche.2011.05.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Lavi Y, Burg A, Maimon E, Meyerstein D. Inside Cover: Electron Exchange Columns through Entrapment of a Nickel Cyclam in a Sol-Gel Matrix (Chem. Eur. J. 18/2011). Chemistry 2011. [DOI: 10.1002/chem.201190088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lavi Y, Burg A, Maimon E, Meyerstein D. Electron exchange columns through entrapment of a nickel cyclam in a sol-gel matrix. Chemistry 2011; 17:5188-92. [PMID: 21465586 DOI: 10.1002/chem.201003451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Indexed: 11/09/2022]
Abstract
An electron exchange column (analogous to ion exchange columns) was developed using the unique redox properties of the nickel-tetraazamacrocyclic complexes (nickel cyclam [Ni(II)L(1)](2+)) and nickel-trans-III-meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, ([Ni(II)L(2)](2+)), and the physical and chemical stability of the ceramic materials using the sol-gel process to entrap the complexes. The entrapment by the biphasic sol-gel method is based on non-covalent bonds between the matrix and the complex; therefore the main problem was leaching. Parameters controlling the leaching were investigated. Redox cycles with the reducing agent ascorbic acid, and persulfate as the oxidizing agent were performed.
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Shamir D, Zilbermann I, Maimon E, Shames AI, Cohen H, Meyerstein D. Anions as stabilizing ligands for Ni(III)(cyclam) in aqueous solutions. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.03.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Schutz O, Masarwa A, Zilbermann I, Maimon E, Cohen H, Meyerstein D. On the mechanism of reduction of maleate by a Co(I) complex with a macrocylic ligand in aqueous solutions. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.499938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Osnat Schutz
- a Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva, Israel
| | - Alexandra Masarwa
- a Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva, Israel
| | - Israel Zilbermann
- b Department of Chemistry , Nuclear Research Centre Negev , Beer-Sheva, Israel
| | - Eric Maimon
- b Department of Chemistry , Nuclear Research Centre Negev , Beer-Sheva, Israel
| | - Haim Cohen
- a Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva, Israel
- c Department of Biological Chemistry , Ariel University Center of Samaria , Ariel, Israel
| | - Dan Meyerstein
- a Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva, Israel
- c Department of Biological Chemistry , Ariel University Center of Samaria , Ariel, Israel
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Popivker I, Zilbermann I, Maimon E, Shamir D, Meyerstein N, Meyerstein D. On the reaction mechanism of MoS42− with nitric oxide. INORG CHEM COMMUN 2010. [DOI: 10.1016/j.inoche.2010.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kats L, Maimon E, Meyerstein D. Substantial Inverse Isotope Effects in the Hydrogen Atom Abstraction from [(L)ClRhIIIH/D]+Macrocyclic Complexes by Methyl Radicals in Aqueous Solutions. Chemistry 2010; 16:460-3. [DOI: 10.1002/chem.200902632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rasnoshik H, Masarwa A, Cohen H, Zilbermann I, Maimon E, Meyerstein D. On the mechanism of reduction of maleate and fumarate by NiI(1,4,8,11-tetraazacyclotetradecane)+ in aqueous solutions. Dalton Trans 2010; 39:823-33. [DOI: 10.1039/b911725c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Eckshtain M, Zilbermann I, Mahammed A, Saltsman I, Okun Z, Maimon E, Cohen H, Meyerstein D, Gross Z. Superoxide dismutase activity of corrole metal complexes. Dalton Trans 2009:7879-82. [PMID: 19771348 DOI: 10.1039/b911278b] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first report regarding SOD activity of metallocorroles, investigated via the combination of the cytochrome C assay, pulse radiolysis, and electrochemistry, is used for identifying the main criteria needed for achieving good performance, as well as for elucidating mechanistic aspects of their action.
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Affiliation(s)
- Meital Eckshtain
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 32000, Israel
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Shamir D, Zilbermann I, Maimon E, Gellerman G, Cohen H, Meyerstein D. Reductive Nitrosation of Peptides Ligated to High-Valent Metal Cations. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700867] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Burg A, Maimon E, Cohen H, Meyerstein D. Ligand Effects on the Chemical Activity of Copper(I) Complexes: Outer- and Inner-Sphere Oxidation of CuIL. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200600702] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kurzion-Zilbermann T, Masarwa A, Maimon E, Cohen H, Meyerstein D. Mechanism of reaction of alkyl radicals with (NiIIL)2+ complexes in aqueous solutions. Dalton Trans 2007:3959-65. [PMID: 17893794 DOI: 10.1039/b706491h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of methyl radicals, *CH3, with the macrocyclic complexes Ni(II)L(1-5) (L(1-5) = cyclam derivatives, vide infra) and Ni(II)edta in aqueous solutions were studied. Methyl radicals react with all these nickel complexes, forming intermediates with Ni(III)-C sigma-bonds. The L(m)Ni(III)-CH3 complexes are formed in equilibria processes with relatively fast forward rate constants of k(f) > 1 x 10(8) M(-1) s(-1) (except in the case of NiL2-trans I cyclam, where the reaction is slower). In all cases the decomposition of the transient complexes occurs via the homolytic cleavage of the metal-carbon sigma-bond. When the homolysis is relatively slow, an isomerisation process of the transient is also observed with the exception of NiL2, where no isomerisation was observed. The results suggest that the strength of the Ni(III)-CH3sigma-bond is mainly affected by steric hindrance.
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Shamir D, Zilbermann I, Maimon E, Shames AI, Cohen H, Meyerstein D. Pyrophosphate and ATP as Stabilizing Ligands for High‐Valent Nickel Complexes. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200500891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Dror Shamir
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Chemistry Department, Nuclear Research Centre Negev, Beer‐Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Chemistry Department, Nuclear Research Centre Negev, Beer‐Sheva, Israel
| | - Alexander I. Shames
- Department of Physics, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
| | - Haim Cohen
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Biological Chemistry Department, College of Judea and Samaria, Ariel, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel
- Biological Chemistry Department, College of Judea and Samaria, Ariel, Israel
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Maimon E, Zilbermann I, Cohen H, Kost D, van Eldik R, Meyerstein D. Mechanism of Isomerization of Ni(cyclam) in Aqueous Solutions. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200500523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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