NO Dismutase Activity of Seven-Coordinate Manganese(II) Pentaazamacrocyclic Complexes
| Autor: | Vesna Niketić, Katharina Duerr, Robert Zimmermann, Milos R. Filipovic, Vladica Simeunović, Miloš Mojović, Ivana Ivanović-Burmazović |
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| Rok vydání: | 2008 |
| Předmět: |
Macrocyclic Compounds
Stereochemistry Inorganic chemistry Molecular Conformation Disproportionation Ligands Nitric Oxide 010402 general chemistry 01 natural sciences Redox Catalysis Superoxide dismutase chemistry.chemical_compound Nucleophile Organometallic Compounds Reactivity (chemistry) Aza Compounds Manganese biology Superoxide Dismutase 010405 organic chemistry Superoxide Stereoisomerism General Chemistry 0104 chemical sciences Enzyme Activation chemistry biology.protein Dismutase Peroxynitrite |
| Zdroj: | Angewandte Chemie International Edition. 47:8735-8739 |
| ISSN: | 1521-3773 1433-7851 |
| Popis: | Seven-coordinate Mn pentaazamacrocyclic complexes represent the most potent synthetic mimics of native superoxide dismutase (SOD), which catalyze dismutation of superoxide (O2C ) into O2 andH2O2 with efficiency that can exceed that of the mitochondrial MnSOD. A number of studies demonstrated the ability of these SOD mimics to protect cells and tissues from oxidative damage caused by superoxide (and/or the product of its reaction with nitric oxide, peroxynitrite), for example in inflammation and oxidation reperfusion injury. The members of this class of SODmimics have entered Phase II clinical trials in the USA. It is emphasized that the major advantage of Mn pentaazamacrocycles over other SOD mimics is their high selectivity for O2C and lack of reactivity with NO, a key molecule in biological processes. However, direct studies of the reaction between NO and this class of complexes, which would support such claims, have not been reported. Various metal complexes, including manganese complexes, react readily with NO, either to yield metal nitrosyls, or to produce N2O and metal nitrite complexes by NO disproportionation. Coordinated NO in metal nitrosyls can exist in one of its three formal redox states NO, NO, and NO . For a number of NO and NO complexes reactivity towards selected nucleophiles and electrophiles, respectively, has been documented. We demonstrated recently that natural MnSOD enzyme reacts with NO according to distinct catalytic NO disproportionation (dismutation) mechanism which yields both reactive species NO and NO . Collectively these results prompted us to (re)examine the reaction of these complexes with NO. The chosen approach has been 1) to establish the reactivity of complexes with NO, 2) to establish the mechanistic details of the reaction, and 3) to demonstrate the potential validity of the complex reaction with NO in a biological setting. In the present study we used [Mn(pyane)Cl2] (1), [8] as a general representative of this class of SOD mimics, and its |
| Databáze: | OpenAIRE |
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