Difference between revisions of "Gnaiger 2000 Proc Natl Acad Sci U S A"
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{{Publication | {{Publication | ||
|title=Gnaiger E, Méndez G, Hand SC (2000) High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia. Proc Natl Acad Sci U S A 97: 11080- | |title=Gnaiger E, Méndez G, Hand SC (2000) High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia. Proc Natl Acad Sci U S A 97:11080-5. | ||
|info=[http://www.ncbi.nlm.nih.gov/pubmed/11005877 PMID: 11005877 Open Access] | |info=[http://www.ncbi.nlm.nih.gov/pubmed/11005877 PMID: 11005877 Open Access] | ||
|authors=Gnaiger | |authors=Gnaiger Erich, Mendez Gabriela, Hand Steven C | ||
|year=2000 | |year=2000 | ||
|journal=Proc Natl Acad Sci U S A | |journal=Proc Natl Acad Sci U S A | ||
|abstract=Mitochondria are confronted with low oxygen levels in the microenvironment within tissues; yet, isolated mitochondria are routinely studied under air-saturated conditions that are effectively hyperoxic, increase oxidative stress, and may impair mitochondrial function. Under hypoxia, on the other hand, respiration and ATP supply are restricted. Under these conditions of oxygen limitation, any compromise in the coupling of oxidative phosphorylation to oxygen consumption could accentuate ATP depletion, leading to metabolic failure. To address this issue, we have developed the approach of oxygen-injection microcalorimetry and ADP-injection respirometry for evaluating mitochondrial function at limiting oxygen supply. Whereas phosphorylation efficiency drops during ADP limitation at high oxygen levels, we show here that oxidative phosphorylation is more efficient at low oxygen than at air saturation, as indicated by higher ratios of ADP flux to total oxygen flux at identical submaximal rates of ATP synthesis. At low oxygen, the proton leak and uncoupled respiration are depressed, thus reducing maintenance energy expenditure. This indicates the importance of low intracellular oxygen levels in avoiding oxidative stress and protecting bioenergetic efficiency. | |abstract=Mitochondria are confronted with low oxygen levels in the microenvironment within tissues; yet, isolated mitochondria are routinely studied under air-saturated conditions that are effectively hyperoxic, increase oxidative stress, and may impair mitochondrial function. Under hypoxia, on the other hand, respiration and ATP supply are restricted. Under these conditions of oxygen limitation, any compromise in the coupling of oxidative phosphorylation to oxygen consumption could accentuate ATP depletion, leading to metabolic failure. To address this issue, we have developed the approach of oxygen-injection microcalorimetry and ADP-injection respirometry for evaluating mitochondrial function at limiting oxygen supply. Whereas phosphorylation efficiency drops during ADP limitation at high oxygen levels, we show here that oxidative phosphorylation is more efficient at low oxygen than at air saturation, as indicated by higher ratios of ADP flux to total oxygen flux at identical submaximal rates of ATP synthesis. At low oxygen, the proton leak and uncoupled respiration are depressed, thus reducing maintenance energy expenditure. This indicates the importance of low intracellular oxygen levels in avoiding oxidative stress and protecting bioenergetic efficiency. | ||
|mipnetlab= | |mipnetlab=AT Innsbruck Gnaiger E, US LA Baton Rouge Hand SC | ||
}} | }} | ||
== Further details == | |||
:::* Gnaiger E (2001) Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply. Respir Physiol 128:277-97. [[Gnaiger 2001 Respir Physiol |»Bioblast link«]] | |||
:::* Gnaiger E (2014) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 4th ed. Mitochondr Physiol Network 19.12. Oroboros MiPNet Publications, Innsbruck:80 pp. - [[Gnaiger 2014 MitoPathways |»Bioblast link«]] with update on terminology and [[biochemical coupling efficiency]]. | |||
::::» [[OXPHOS-coupling efficiency]] | |||
::::» [[ETS coupling efficiency]] | |||
:::* [http://www.ncbi.nlm.nih.gov/pubmed?db=pubmed&cmd=link&linkname=pubmed_pubmed_citedin&uid=11005877 Citations] | |||
{{Labeling | {{Labeling | ||
|area=Respiration, Comparative MiP;environmental MiP, Developmental biology | |||
|organism=Rat, Artemia, Crustaceans | |||
|tissues=Liver | |||
|preparations=Isolated mitochondria | |||
|topics=ADP, ATP, Coupling efficiency;uncoupling, Oxygen kinetics | |||
|couplingstates=LEAK, OXPHOS | |||
|pathways=S | |||
|instruments=Oxygraph-2k, TIP2k | |instruments=Oxygraph-2k, TIP2k | ||
| | |additional=Tissue normoxia, ATP, Steady state | ||
}} | }} | ||
Revision as of 15:45, 7 July 2020
Gnaiger E, Méndez G, Hand SC (2000) High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia. Proc Natl Acad Sci U S A 97:11080-5. |
Gnaiger Erich, Mendez Gabriela, Hand Steven C (2000) Proc Natl Acad Sci U S A
Abstract: Mitochondria are confronted with low oxygen levels in the microenvironment within tissues; yet, isolated mitochondria are routinely studied under air-saturated conditions that are effectively hyperoxic, increase oxidative stress, and may impair mitochondrial function. Under hypoxia, on the other hand, respiration and ATP supply are restricted. Under these conditions of oxygen limitation, any compromise in the coupling of oxidative phosphorylation to oxygen consumption could accentuate ATP depletion, leading to metabolic failure. To address this issue, we have developed the approach of oxygen-injection microcalorimetry and ADP-injection respirometry for evaluating mitochondrial function at limiting oxygen supply. Whereas phosphorylation efficiency drops during ADP limitation at high oxygen levels, we show here that oxidative phosphorylation is more efficient at low oxygen than at air saturation, as indicated by higher ratios of ADP flux to total oxygen flux at identical submaximal rates of ATP synthesis. At low oxygen, the proton leak and uncoupled respiration are depressed, thus reducing maintenance energy expenditure. This indicates the importance of low intracellular oxygen levels in avoiding oxidative stress and protecting bioenergetic efficiency.
• O2k-Network Lab: AT Innsbruck Gnaiger E, US LA Baton Rouge Hand SC
Further details
- Gnaiger E (2001) Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply. Respir Physiol 128:277-97. »Bioblast link«
- Gnaiger E (2014) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 4th ed. Mitochondr Physiol Network 19.12. Oroboros MiPNet Publications, Innsbruck:80 pp. - »Bioblast link« with update on terminology and biochemical coupling efficiency.
Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Developmental biology
Organism: Rat, Artemia, Crustaceans
Tissue;cell: Liver
Preparation: Isolated mitochondria
Regulation: ADP, ATP, Coupling efficiency;uncoupling, Oxygen kinetics Coupling state: LEAK, OXPHOS Pathway: S HRR: Oxygraph-2k, TIP2k
Tissue normoxia, ATP, Steady state