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Gnaiger 2011 Abstract-MonteVerita
Coupling states OXPHOS  +
Has abstract '''Mitochondrial capacity''': [[OXPHOS]] c
'''Mitochondrial capacity''': [[OXPHOS]] capacity is evaluated in isolated mitochondria (mt) and permeabilized cells with physiological substrate cocktails to reconstitute tricarboxylic acid cycle function. As a consequence, convergent electron flow from Complexes CI+II of the electron transfer-pathway ([[ET-pathway]]) to the [[Q-junction]] exerts an additive effect on flux [1]. '''Oxygen kinetics of mt-respiration''': The apparent ''K''<sub>m,O2</sub> or ''c''<sub>50</sub> [µM] (''p''<sub>50</sub> [kPa]) of mt-respiration increases linearly with respiratory capacity controlled by metabolic state, from 0.2 to 1.6 µM determined by [[high-resolution respirometry]]. O<sub>2</sub> gradients are significant only in large cells including cardiomyocytes. The apparent ''p''<sub>50</sub> increases 100-fold in permeabilized muscle fibers due to diffusion gradients [2]. '''mt-function at ''V''<sub>O2max</sub>''': Aerobic capacity of the human leg muscle exceeds maximum O<sub>2</sub> uptake of isolated mitochondria [3] and v. lateralis during ''V''<sub>O2max</sub> [4]. Therefore, oxygen supply limits aerobic performance, proportional to the apparent mt-excess capacity [5]. mt-respiration is more sensitive to average ''p''<sub>O2</sub> in heterogenous tissues than under homogenous conditions in vitro. Tissue heterogeneity increases the kinetic dependence of flux on average intracellular ''p''<sub>O2</sub>. High mt-density reinforces the steepness of oxygen gradients and oxygen heterogeneity in the tissue, contributing to the O<sub>2</sub> limitation in athletic vs sedentary individuals at ''V''<sub>O2max</sub> [6]. This provides a functional rationale for the observation that hypoxia does not specifically trigger mt-biogenesis [7]. Contribution to K-Regio ''[[MitoCom_O2k-Fluorometer|MitoCom Tyrol]]''. [1] [[Gnaiger 2009 Int J Biochem Cell Biol|Gnaiger 2009]]; [[Lemieux_2011_Int J Biochem Cell Biol|Lemieux et al 2011 Int J Biochem Cell Biol]] [2] [[Gnaiger_2003_Adv Exp Med Biol|Gnaiger 2003]]; [[Scandurra_2010_Adv Exp Med Biol|Scandurra, Gnaiger 2010 Adv Exp Med Biol]]. [3] Rasmussen et al 2001 AJP. [4] [[Boushel_2011_Mitochondrion|Boushel et al 2011 Mitochondrion]]. [5] [[Gnaiger_1998_J_Exp_Biol|Gnaiger et al 1998 JEB]]. [6] Richardson et al; Haseler et al JAP. [7] [[Pesta_2011_AJP|Pesta et al 2011 AJP]]; [[Jacobs_2011_J_Appl_Physiol|Jacobs et al 2011 JAP]].
11_J_Appl_Physiol|Jacobs et al 2011 JAP]].  +
Has title Gnaiger E (2011) Mitochondrial respiratory capacity at maximum aerobic exercise levels: Are intracellular oxygen levels limiting? Abstract Monte Verita.  +
Instrument and method Oxygraph-2k  +
Mammal and model Human  +
MiP area Respiration  +
Pathways N  + , S  + , NS  +
Respiration and regulation Oxygen kinetics  + , Substrate  +
Was published by MiPNetLab AT Innsbruck Gnaiger E +
Was submitted in year 2011  +
Was submitted to event Monte Verita +
Was written by Gnaiger E +
Categories Abstracts
Modification date
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13:06:06, 20 October 2017  +
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