Difference between revisions of "Neufer 2014 Abstract MiP2014"
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|abstract=The biochemical efficiency of oxidative phosphorylation (OXPHOS), quantified as the amount of ATP produced per oxygen atom consumed (ATP/O), is vital to maintaining proper myocyte energetics. However, despite its central importance, it is difficult to experimentally determine the | |abstract=The biochemical efficiency of oxidative phosphorylation (OXPHOS), quantified as the amount of ATP produced per oxygen atom consumed (ATP/O or ~P/O), is vital to maintaining proper myocyte energetics. However, despite its central importance, it is difficult to experimentally determine the ~P/O ratio as a function of metabolic demand, and therefore, the relationship between OXPHOS efficiency and metabolic demand is poorly understood. O<sub>2</sub> consumption (high-resolution respirometry) and ATP production (determined fluorometrically using a 2-deoxyglucose – hexokinase – glucose-6-phosphate dehydrogenase – NADP<sup>+</sup> respiratory clamp system [1]), rates were measured simultaneously in permeabilized mouse oxidative and glycolytic skeletal muscle fiber bundles using a customized OROBOROS Oxygraph-2k. | ||
With pyruvate+malate (5+2 mM) as substrate, at low [ADP] (5-20 µM), the ~P/O ratio increased as a function of [ADP], independent of an increase in O<sub>2</sub> consumption. Maximal ~P/O peaked at ~2.0 and was not different between oxidative and glycolytic muscle. Pharmacological inhibition of adenylate kinase decreased ATP production rate but did not alter ADP-dependent increases in OXPHOS efficiency. | |||
These findings suggest that mitochondria respond to low levels of metabolic demand by initially increasing OXPHOS efficiency. | These findings suggest that mitochondria respond to low levels of metabolic demand by initially increasing OXPHOS efficiency. | ||
Revision as of 07:50, 12 August 2014
| Assessing ATP production and oxygen consumption simultaneously in permeabilized fibers: ATP/O. |
Link:
MiP2014, Book of Abstracts Open Access
Lark DS, Ryan T, Anderson EJ, Neufer DP (2014)
Event: MiP2014
The biochemical efficiency of oxidative phosphorylation (OXPHOS), quantified as the amount of ATP produced per oxygen atom consumed (ATP/O or ~P/O), is vital to maintaining proper myocyte energetics. However, despite its central importance, it is difficult to experimentally determine the ~P/O ratio as a function of metabolic demand, and therefore, the relationship between OXPHOS efficiency and metabolic demand is poorly understood. O2 consumption (high-resolution respirometry) and ATP production (determined fluorometrically using a 2-deoxyglucose – hexokinase – glucose-6-phosphate dehydrogenase – NADP+ respiratory clamp system [1]), rates were measured simultaneously in permeabilized mouse oxidative and glycolytic skeletal muscle fiber bundles using a customized OROBOROS Oxygraph-2k.
With pyruvate+malate (5+2 mM) as substrate, at low [ADP] (5-20 µM), the ~P/O ratio increased as a function of [ADP], independent of an increase in O2 consumption. Maximal ~P/O peaked at ~2.0 and was not different between oxidative and glycolytic muscle. Pharmacological inhibition of adenylate kinase decreased ATP production rate but did not alter ADP-dependent increases in OXPHOS efficiency.
These findings suggest that mitochondria respond to low levels of metabolic demand by initially increasing OXPHOS efficiency.
• O2k-Network Lab: US NC Greenville Neufer PD, US NC Greenville East Carolina Univ
Labels: MiParea: Respiration
Organism: Mouse
Tissue;cell: Skeletal muscle
Preparation: Permeabilized tissue
Regulation: ADP, ATP production, Coupling efficiency;uncoupling Coupling state: OXPHOS
HRR: Oxygraph-2k
MiP2014
Affiliation
1-East Carolina Diabetes Obesity Inst; 2-Dep Kinesiolog; 3-Dep Physiol; 4-Dep Pharmacolog Toxicolog; East Carolina Univ, Greenville, NC, USA. – [email protected]
References and acknowledgements
Supported by: National Institute of Health R01 DK096907 (USA).
- Gouspillou G, Rouland R, Calmettes G, Deschodt-Arsac V, Franconi J-M, Bourdel-Marchasson I, Diolez P (2011) Accurate determination of the oxidative phosphorylation affinity for ADP in isolated mitochondria. PloS One 6:e20709.
