Scandroglio 2014 Free Radic Res: Difference between revisions
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provide a control mechanism to prevent O<sub>2</sub> | provide a control mechanism to prevent O<sub>2</sub> | ||
<sup>.-</sup> and H<sub>2</sub>O<sub>2</sub> formation by the respiratory chain. | <sup>.-</sup> and H<sub>2</sub>O<sub>2</sub> formation by the respiratory chain. | ||
|keywords=Aconitase 2, Free radicals, Hydrogen peroxide, Metabolic control, Mitochondria, Superoxide radical | |keywords=Aconitase 2, Free radicals, Hydrogen peroxide, Metabolic control, Mitochondria, Superoxide radical, Amplex Red, Safranin | ||
|mipnetlab=UY Montevideo Radi R | |mipnetlab=UY Montevideo Radi R | ||
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|tissues=Heart, Nervous system, Liver, Kidney | |tissues=Heart, Nervous system, Liver, Kidney | ||
|preparations=Isolated mitochondria | |preparations=Isolated mitochondria | ||
|couplingstates= | |couplingstates=LEAK, OXPHOS | ||
|substratestates=CI, CII | |substratestates=CI, CII | ||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
}} | }} |
Revision as of 17:33, 28 January 2016
Scandroglio F, Tortora V, Radi R, Castro L (2014) Metabolic control analysis of mitochondrial aconitase: influence over respiration and mitochondrial superoxide and hydrogen peroxide production. Free Radic Res 48:684-93. |
Scandroglio F, Tortora V, Radi R, Castro L (2014) Free Radic Res
Abstract: The Fe-S cluster of mitochondrial aconitase is rapidly and selectively inactivated by oxidants, yielding an inactive enzyme that can be reactivated by reductants and iron in vivo. In order to elucidate the metabolic impact of oxidant-dependent aconitase inhibition over the citric acid cycle, the respiratory chain reactions, and reactive species formation, we performed a metabolic analysis using isolated mitochondria from different rat tissues. Titrations with fluorocitrate showed IC50 for aconitase inhibition ranging from 7 to 24 mM. The aconitase inhibition threshold in mitochondrial oxygen consumption was determined to range from 63 to 98%. Of the tissues examined, brain and heart exhibited the highest values in the flux control coefficient (< 0.95). Aconitase-specific activity varied widely among tissues examined from ~60 mU/mg in liver to 321 mU/mg in kidney at 21% O2. In brain and heart, aconitase-specific activity increased by 42 and 12%, respectively, at 2% O2 reflecting aconitase inactivation by oxygen-derived oxidants at 21% O2. Both mitochondrial membrane potential and hydrogen peroxide production significantly decreased upon aconitase inhibition in heart and brain mitochondria. These results indicate that aconitase can exert control over respiration (with tissue specificity) and support the hypothesis that inactivation of aconitase may provide a control mechanism to prevent O2 .- and H2O2 formation by the respiratory chain. โข Keywords: Aconitase 2, Free radicals, Hydrogen peroxide, Metabolic control, Mitochondria, Superoxide radical, Amplex Red, Safranin
โข O2k-Network Lab: UY Montevideo Radi R
Labels: MiParea: Respiration
Organism: Rat
Tissue;cell: Heart, Nervous system, Liver, Kidney
Preparation: Isolated mitochondria
Coupling state: LEAK, OXPHOS
HRR: Oxygraph-2k