Difference between revisions of "P/E control ratio"
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{{MitoPedia | {{MitoPedia | ||
|abbr=''P/E'' | |abbr=''P/E'' | ||
|description=[[Image:P over E.jpg|50 px|OXPHOS control ratio]] The '''OXPHOS control ratio''' or ''P/E'' coupling control ratio ([[OXPHOS]]/[[ | |description=[[Image:P over E.jpg|50 px|OXPHOS control ratio]] The '''OXPHOS control ratio''' or ''P/E'' coupling control ratio ([[OXPHOS]]/[[ET-pathway]]; phosphorylation system control ratio) is an expression of the limitation of OXPHOS capacity by the [[phosphorylation system]]. The relative limitation of OXPHOS capacity by the capacity of the phosphorylation system is better expressed by the [[Excess E-P capacity factor |excess ''E-P'' capacity factor]], ''j<sub>ExP</sub>'' = 1-''P/E''. The ''P/E'' ratio increases with increasing capacity of the phosphorylation system up to a maximum of 1.0 when it matches or is in excess of ET capacity. ''P/E'' also increases with uncoupling. ''P/E'' increases from the lower boundary set by ''[[L/E]]'' (zero capacity of the phosphorylation system), to the upper limit of 1.0, when there is no limitation of ''P'' by the phosphorylation system or the proton backpressure (capacity of the phosphorylation system fully matches the [[ET capacity]]; or if the system is fully [[uncoupled]]). It is important to separate the kinetic effect of ADP limitation from limitation by enzymatic capacity at saturating ADP concentration. | ||
» [[#P.2FE_from_mouse_to_man |'''MiPNet article''']] | » [[#P.2FE_from_mouse_to_man |'''MiPNet article''']] | ||
|info=[[Gnaiger 2014 MitoPathways]], [[Gnaiger 2009 Int J Biochem Cell Biol]], [[Pesta 2012 Methods Mol Biol]] | |info=[[Gnaiger 2014 MitoPathways]], [[Gnaiger 2009 Int J Biochem Cell Biol]], [[Pesta 2012 Methods Mol Biol]] | ||
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|year=2014 | |year=2014 | ||
|journal=MiPNet | |journal=MiPNet | ||
|abstract=Variability of the ''P/E'' depends in part on [[Uncoupler |coupling]] of [[OXPHOS]], but mainly results from a diversity in the apparent [[ | |abstract=Variability of the ''P/E'' depends in part on [[Uncoupler |coupling]] of [[OXPHOS]], but mainly results from a diversity in the apparent [[ET-pathway]] excess capacity over the capacity of the [[phosphorylation system]] in different species, tissues and cell lines. | ||
|mipnetlab=AT Innsbruck Gnaiger E | |mipnetlab=AT Innsbruck Gnaiger E | ||
}} | }} | ||
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|instruments=Theory | |instruments=Theory | ||
}} | }} | ||
:::: When using animal (specifically mouse) versus human muscle tissue, it is important to be aware of the fact that human muscle shows a significant apparent excess capacity of the | :::: When using animal (specifically mouse) versus human muscle tissue, it is important to be aware of the fact that human muscle shows a significant apparent excess capacity of the ET-pathway versus the phosphorylation system with physiological substrate combinations (''P/E''<1.0), in contrast to mouse skeletal and cardiac tissue (''P/E''=0.97 to 1.0). Therefore, uncoupler titrations (to estimate ET capacity, ''E'') following ADP stimulation (to estimate OXPHOS capacity, ''P'') are different: The optimum uncoupler concentration can be estimated by stepwise titration from the ''P'' state to the ''E'' state in human muscle mitochondria. In mouse muscle mitochondria, this is not possible if ''P/E''=1.0, since under these respiratory control conditions there is no stimulation of respiration at any uncoupler concentration, but only inhibition at increasing uncoupler concentrations. | ||
:::: To show the actual action of the uncoupler in such mitochondria, a control experiment must be carried out when titrating uncoupler in the absence of ADP, to see the actual stimulation from the LEAK state (''L'') to the | :::: To show the actual action of the uncoupler in such mitochondria, a control experiment must be carried out when titrating uncoupler in the absence of ADP, to see the actual stimulation from the LEAK state (''L'') to the ET-pathway state (''E''). | ||
== Can ''P/E'' be higher than 1.0? == | == Can ''P/E'' be higher than 1.0? == | ||
:::: [[OXPHOS]] capacity can be less than or equal to [[ | :::: [[OXPHOS]] capacity can be less than or equal to [[ET-pathway]] capacity, but it cannot be higher. Any result giving ''P/E''>1.0 is due to an experimental artefact. Such an artefact may be obtained due to application of an inhibitory uncoupler concentration, or inhibition of ET-pathway by inhibitors of a component of the [[phosphorylation system]]. | ||
::::* The ''P/E'' ratio is also discussed in: [[ | ::::* The ''P/E'' ratio is also discussed in: [[ET capacity]]; compare [[Excess E-P capacity factor |excess ''E-P'' capacity factor]]. | ||
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= List of publications: OXPHOS and | = List of publications: OXPHOS and ET-pathway = | ||
{{#ask:[[Category:Publications]] [[Coupling states::OXPHOS]] [[Coupling states::ETS]] | {{#ask:[[Category:Publications]] [[Coupling states::OXPHOS]] [[Coupling states::ETS]] | ||
|?Was published in year=Year | |||
|?Has title=Reference | |||
|?Mammal and model | |||
|?Tissue and cell | |||
|?Stress | |||
|?Diseases | |||
|format=broadtable | |||
|limit=5000 | |||
|offset=0 | |||
|sort=Was published in year | |||
|order=descending | |||
}} | |||
{{#ask:[[Category:Publications]] [[Coupling states::OXPHOS]] [[Coupling states::ET-pathway]] | |||
|?Was published in year=Year | |?Was published in year=Year | ||
|?Has title=Reference | |?Has title=Reference |
Revision as of 09:20, 20 October 2017
Description
The OXPHOS control ratio or P/E coupling control ratio (OXPHOS/ET-pathway; phosphorylation system control ratio) is an expression of the limitation of OXPHOS capacity by the phosphorylation system. The relative limitation of OXPHOS capacity by the capacity of the phosphorylation system is better expressed by the excess E-P capacity factor, jExP = 1-P/E. The P/E ratio increases with increasing capacity of the phosphorylation system up to a maximum of 1.0 when it matches or is in excess of ET capacity. P/E also increases with uncoupling. P/E increases from the lower boundary set by L/E (zero capacity of the phosphorylation system), to the upper limit of 1.0, when there is no limitation of P by the phosphorylation system or the proton backpressure (capacity of the phosphorylation system fully matches the ET capacity; or if the system is fully uncoupled). It is important to separate the kinetic effect of ADP limitation from limitation by enzymatic capacity at saturating ADP concentration. » MiPNet article
Abbreviation: P/E
Reference: Gnaiger 2014 MitoPathways, Gnaiger 2009 Int J Biochem Cell Biol, Pesta 2012 Methods Mol Biol
MitoPedia concepts:
Respiratory control ratio
MitoPedia methods:
Respirometry
P/E from mouse to man
Gnaiger E (2014) P/E from mouse to man. Mitochondr Physiol Network 2014-05-20. |
Abstract: Variability of the P/E depends in part on coupling of OXPHOS, but mainly results from a diversity in the apparent ET-pathway excess capacity over the capacity of the phosphorylation system in different species, tissues and cell lines.
• O2k-Network Lab: AT Innsbruck Gnaiger E
Labels:
Regulation: Coupling efficiency;uncoupling
Coupling state: OXPHOS, ETS"ETS" is not in the list (LEAK, ROUTINE, OXPHOS, ET) of allowed values for the "Coupling states" property.
HRR: Theory
- When using animal (specifically mouse) versus human muscle tissue, it is important to be aware of the fact that human muscle shows a significant apparent excess capacity of the ET-pathway versus the phosphorylation system with physiological substrate combinations (P/E<1.0), in contrast to mouse skeletal and cardiac tissue (P/E=0.97 to 1.0). Therefore, uncoupler titrations (to estimate ET capacity, E) following ADP stimulation (to estimate OXPHOS capacity, P) are different: The optimum uncoupler concentration can be estimated by stepwise titration from the P state to the E state in human muscle mitochondria. In mouse muscle mitochondria, this is not possible if P/E=1.0, since under these respiratory control conditions there is no stimulation of respiration at any uncoupler concentration, but only inhibition at increasing uncoupler concentrations.
- To show the actual action of the uncoupler in such mitochondria, a control experiment must be carried out when titrating uncoupler in the absence of ADP, to see the actual stimulation from the LEAK state (L) to the ET-pathway state (E).
Can P/E be higher than 1.0?
- OXPHOS capacity can be less than or equal to ET-pathway capacity, but it cannot be higher. Any result giving P/E>1.0 is due to an experimental artefact. Such an artefact may be obtained due to application of an inhibitory uncoupler concentration, or inhibition of ET-pathway by inhibitors of a component of the phosphorylation system.
- The P/E ratio is also discussed in: ET capacity; compare excess E-P capacity factor.
Biochemical coupling efficiency: from 0 to <1
- More details » Biochemical coupling efficiency