Gnaiger 2000 Proc Natl Acad Sci U S A: Difference between revisions
No edit summary |
No edit summary |
||
Line 25: | Line 25: | ||
|pathways=S | |pathways=S | ||
|instruments=Oxygraph-2k, TIP2k | |instruments=Oxygraph-2k, TIP2k | ||
|additional=Tissue normoxia, ATP, Steady state | |additional=Tissue normoxia, ATP, Steady state, BEC 2020.2 | ||
}} | }} |
Revision as of 00:37, 2 January 2021
Gnaiger E, MΓ©ndez 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.
β’ 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. Β»Bioblast linkΒ«
- Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. Bioenerg Commun:112 pp. - Β»Bioblast linkΒ« 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, BEC 2020.2