Gnaiger 2002 Biochem Soc Trans: Difference between revisions
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|title=Gnaiger E, Kuznetsov AV (2002) Mitochondrial respiration at low levels of oxygen and cytochrome ''c''. Biochem Soc Trans 30:242-8. | |title=Gnaiger E, Kuznetsov AV (2002) Mitochondrial respiration at low levels of oxygen and cytochrome ''c''. Biochem Soc Trans 30:242-8. | ||
|info=[ | |info=[https://pubmed.ncbi.nlm.nih.gov/12023860/ PMID 12023860] | ||
|authors=Gnaiger Erich, Kuznetsov AV | |authors=Gnaiger Erich, Kuznetsov AV | ||
|year=2002 | |year=2002 | ||
|journal=Biochem Soc Trans | |journal=Biochem Soc Trans | ||
|abstract=In the intracellular microenvironment of active muscle tissue, high rates of respiration are maintained at near-limiting oxygen concentrations. The respiration of isolated heart mitochondria is a hyperbolic function of oxygen concentration and half-maximal rates were obtained at 0.4 and 0.7 µM O<sub>2</sub> with substrates for the respiratory chain (succinate) and cytochrome c oxidase [N,N,N,N',N'-tetramethyl-''p''-phenylenediamine dihydrochloride (TMPD)ascorbate] respectively at 30 °C and with maximum ADP stimulation ([[OXPHOS]]). | |abstract=In the intracellular microenvironment of active muscle tissue, high rates of respiration are maintained at near-limiting oxygen concentrations. The respiration of isolated heart mitochondria is a hyperbolic function of oxygen concentration and half-maximal rates were obtained at 0.4 and 0.7 µM O<sub>2</sub> with substrates for the respiratory chain (succinate) and cytochrome c oxidase [''N,N,N,N',N'''-tetramethyl-''p''-phenylenediamine dihydrochloride (TMPD)ascorbate] respectively at 30 °C and with maximum ADP stimulation ([[OXPHOS]]). | ||
The respiratory response of cytochrome ''c''-depleted mitoplasts to external cytochrome ''c'' was biphasic with TMPD, but showed a monophasic hyperbolic function with succinate. Half-maximal stimulation of respiration was obtained at 0.4 µM cytochrome ''c'', which was nearly identical to the high-affinity ''K''<sub>m</sub>' for cytochrome ''c'' of cytochrome ''c'' oxidase supplied with TMPD. The capacity of cytochrome ''c'' oxidase in the presence of TMPD was 2-fold higher than the capacity of the respiratory chain with succinate, measured at environmental normoxic levels. This apparent excess capacity, however, is significantly decreased under physiological intracellular oxygen conditions and declines steeply under hypoxic conditions. Similarly, the excess capacity of cytochrome ''c'' oxidase declines with progressive cytochrome ''c'' depletion. The flux control coeficient of cytochrome ''c'' oxidase, therefore, increases as a function of substrate limitation of oxygen and cytochrome ''c'', which suggests a direct functional role for the apparent excess capacity of cytochrome ''c'' oxidase in hypoxia and under conditions of intracellular accumulation of cytochrome ''c'' after its release from mitochondria. | The respiratory response of cytochrome ''c''-depleted mitoplasts to external cytochrome ''c'' was biphasic with TMPD, but showed a monophasic hyperbolic function with succinate. Half-maximal stimulation of respiration was obtained at 0.4 µM cytochrome ''c'', which was nearly identical to the high-affinity ''K''<sub>m</sub>' for cytochrome ''c'' of cytochrome ''c'' oxidase supplied with TMPD. The capacity of cytochrome ''c'' oxidase in the presence of TMPD was 2-fold higher than the capacity of the respiratory chain with succinate, measured at environmental normoxic levels. This apparent excess capacity, however, is significantly decreased under physiological intracellular oxygen conditions and declines steeply under hypoxic conditions. Similarly, the excess capacity of cytochrome ''c'' oxidase declines with progressive cytochrome ''c'' depletion. The flux control coeficient of cytochrome ''c'' oxidase, therefore, increases as a function of substrate limitation of oxygen and cytochrome ''c'', which suggests a direct functional role for the apparent excess capacity of cytochrome ''c'' oxidase in hypoxia and under conditions of intracellular accumulation of cytochrome ''c'' after its release from mitochondria. | ||
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== Cited by == | == Cited by == | ||
::* 34 articles in PubMed (2023-03-27) https://pubmed.ncbi.nlm.nih.gov/12023860/ | |||
{{Template:Cited by Gnaiger 2020 BEC MitoPathways}} | {{Template:Cited by Gnaiger 2020 BEC MitoPathways}} | ||
{{Template:Cited by Silva 2021 MitoFit Etomoxir}} | |||
{{Labeling | {{Labeling | ||
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|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
|additional=BEC 2020.2 | |additional=BEC 2020.2 | ||
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Latest revision as of 21:23, 27 March 2023
| Has title::Gnaiger E, Kuznetsov AV (2002) Mitochondrial respiration at low levels of oxygen and cytochrome ''c''. Biochem Soc Trans 30:242-8. |
» [[Has info::PMID 12023860]]
Was written by::Gnaiger Erich, Was written by::Kuznetsov AV (Was published in year::2002) Was published in journal::Biochem Soc Trans
Abstract: [[has abstract::In the intracellular microenvironment of active muscle tissue, high rates of respiration are maintained at near-limiting oxygen concentrations. The respiration of isolated heart mitochondria is a hyperbolic function of oxygen concentration and half-maximal rates were obtained at 0.4 and 0.7 µM O2 with substrates for the respiratory chain (succinate) and cytochrome c oxidase [N,N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)ascorbate] respectively at 30 °C and with maximum ADP stimulation (OXPHOS).
The respiratory response of cytochrome c-depleted mitoplasts to external cytochrome c was biphasic with TMPD, but showed a monophasic hyperbolic function with succinate. Half-maximal stimulation of respiration was obtained at 0.4 µM cytochrome c, which was nearly identical to the high-affinity Km' for cytochrome c of cytochrome c oxidase supplied with TMPD. The capacity of cytochrome c oxidase in the presence of TMPD was 2-fold higher than the capacity of the respiratory chain with succinate, measured at environmental normoxic levels. This apparent excess capacity, however, is significantly decreased under physiological intracellular oxygen conditions and declines steeply under hypoxic conditions. Similarly, the excess capacity of cytochrome c oxidase declines with progressive cytochrome c depletion. The flux control coeficient of cytochrome c oxidase, therefore, increases as a function of substrate limitation of oxygen and cytochrome c, which suggests a direct functional role for the apparent excess capacity of cytochrome c oxidase in hypoxia and under conditions of intracellular accumulation of cytochrome c after its release from mitochondria.]]
• O2k-Network Lab: Was published by MiPNetLab::AT Innsbruck Gnaiger E, Was published by MiPNetLab::AT Innsbruck Oroboros
Cited by
- 34 articles in PubMed (2023-03-27) https://pubmed.ncbi.nlm.nih.gov/12023860/
- Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. Bioenerg Commun 2020.2. https://doi.org/10.26124/bec:2020-0002
- Silva et al (2021) Off-target effect of etomoxir on mitochondrial Complex I. MitoFit Preprints 2021. (in preparation)
Labels: MiParea: MiP area::Respiration
Organism: Organism::Rat
Tissue;cell: tissue and cell::Heart
Preparation: Preparation::Isolated mitochondria, Preparation::SMP
Regulation: Topic::Cyt c, Topic::Flux control, Topic::Oxygen kinetics, Topic::Threshold;excess capacity Coupling state: Coupling states::OXPHOS Pathway: Pathways::S, Pathways::CIV HRR: Instrument and method::Oxygraph-2k
