Jarmuszkiewicz 2005 Biochim Biophys Acta: Difference between revisions
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{{Labeling | {{Labeling | ||
|area=Respiration | |area=Respiration | ||
| | |organism=Protists | ||
|preparations=Oxidase;biochemical oxidation | |preparations=Oxidase;biochemical oxidation | ||
|enzymes=Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, TCA cycle and matrix dehydrogenases | |enzymes=Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, TCA cycle and matrix dehydrogenases |
Revision as of 10:19, 9 November 2016
Jarmuszkiewicz W, Czarna M, Sluse FE (2005) Substrate kinetics of the Acanthamoeba castellanii alternative oxidase and the effects of GMP. Biochim Biophys Acta 1708:71-8. |
Jarmuszkiewicz W, Czarna M, Sluse FE (2005) Biochim Biophys Acta
Abstract: In Acanthamoeba castellanii mitochondria, the apparent affinity values of alternative oxidase for oxygen were much lower than those for cytochrome c oxidase. For unstimulated alternative oxidase, the KMox values were around 4โ5 ฮผM both in mitochondria oxidizing 1 mM external NADH or 10 mM succinate. For alternative oxidase fully stimulated by 1 mM GMP, the KMox values were markedly different when compared to those in the absence of GMP and they varied when different respiratory substrates were oxidized (KMox was around 1.2 ฮผM for succinate and around 11 ฮผM for NADH). Thus, with succinate as a reducing substrate, the activation of alternative oxidase (with GMP) resulted in the oxidation of the ubiquinone pool, and a corresponding decrease in KMox. However, when external NADH was oxidized, the ubiquinone pool was further reduced (albeit slightly) with alternative oxidase activation, and the KMox increased dramatically. Thus, the apparent affinity of alternative oxidase for oxygen decreased when the ubiquinone reduction level increased either by changing the activator or the respiratory substrate availability. โข Keywords: Mitochondria, Alternative oxidase, GMP stimulation, Acanthamoeba castellanii
Labels: MiParea: Respiration
Organism: Protists
Preparation: Oxidase;biochemical oxidation Enzyme: Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, TCA cycle and matrix dehydrogenases Regulation: Oxygen kinetics Coupling state: OXPHOS Pathway: ROX HRR: Oxygraph-2k