Difference between revisions of "Level flow"
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{{MitoPedia | {{MitoPedia | ||
|abbr=''E'' | |abbr=''E'' | ||
|description=[[File:E.jpg |link=ET | |description=[[File:E.jpg |link=ET capacity]] '''Level flow''' is a [[steady state]] of a system with an input process coupled to an output process (coupled system), in which the output force is zero. ''Clearly, energy must be expended to maintain level flow, even though output is zero'' (Caplan and Essig 1983; referring to zero output force, while output flow may be maximum). | ||
}} | }} | ||
Communicated by [[Gnaiger E]] 2011-02-27, edited 2014-04-23. | |||
== Level flow and State 3 == | == Level flow and State 3 == | ||
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:::: (i) A state of (incompletely) coupled respiration at zero (minimum) phosphorylation potential (and saturating ADP and Pi) supported by an excess of defined reduced substrates, which is [[OXPHOS capacity]], ''P'', at minimum levels of ATP (to maintain the output force or Gibbs force of phosphorylation near zero); | :::: (i) A state of (incompletely) coupled respiration at zero (minimum) phosphorylation potential (and saturating ADP and Pi) supported by an excess of defined reduced substrates, which is [[OXPHOS capacity]], ''P'', at minimum levels of ATP (to maintain the output force or Gibbs force of phosphorylation near zero); | ||
:::: (ii) A state of noncoupled respiration at low mt-membrane potential supported by an excess of defined reduced substrates, which is [[ET | :::: (ii) A state of noncoupled respiration at low mt-membrane potential supported by an excess of defined reduced substrates, which is [[ET capacity]], ''E'', defining the collapsed protonmotive force as (near-zero) output force (independent of ADP and ATP concentrations and the corresponding value of the Gibbs force of phosphorylation). | ||
:::: Since ''E'' may be higher or equal to ''P'', level flow does not sufficiently define a mitochondrial respiratory state, but refers only to the general boundary conditions of a low ouput force. [[State 3]] is a state of ‘high ADP’ (Chance and Williams 1955), without restriction to ‘saturating ADP’. State 3 respiration, therefore, may be less than level flow, if limited by non-saturating ADP concentrations (State 3 respiration < ''P'') or by the capacity of the phosphorylation system (State 3 respiration < ''E''). | :::: Since ''E'' may be higher or equal to ''P'', level flow does not sufficiently define a mitochondrial respiratory state, but refers only to the general boundary conditions of a low ouput force. [[State 3]] is a state of ‘high ADP’ (Chance and Williams 1955), without restriction to ‘saturating ADP’. State 3 respiration, therefore, may be less than level flow, if limited by non-saturating ADP concentrations (State 3 respiration < ''P'') or by the capacity of the phosphorylation system (State 3 respiration < ''E''). | ||
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== Why not 'State 3u'? == | == Why not 'State 3u'? == | ||
::::* ''More details:'' »[[ET | ::::* ''More details:'' »[[ET capacity]] | ||
== Electron transfer-pathway versus electron transport chain == | == Electron transfer-pathway versus electron transport chain == | ||
::::* ''More details:'' »[[Electron transfer-pathway state]] | ::::* ''More details:'' »[[Electron-transfer-pathway state]] | ||
== Biochemical coupling efficiency: from 0 to <1 == | == Biochemical coupling efficiency: from 0 to <1 == | ||
::::* ''More details:'' »[[Biochemical coupling efficiency]] | ::::* ''More details:'' »[[Biochemical coupling efficiency]] | ||
{{MitoPedia concepts | |||
|mitopedia concept=Respiratory state, Find, Ergodynamics | |||
}} | |||
{{MitoPedia topics | |||
|mitopedia topic=EAGLE | |||
}} | |||
Latest revision as of 15:00, 8 June 2020
- high-resolution terminology - matching measurements at high-resolution
Level flow
Description
Level flow is a steady state of a system with an input process coupled to an output process (coupled system), in which the output force is zero. Clearly, energy must be expended to maintain level flow, even though output is zero (Caplan and Essig 1983; referring to zero output force, while output flow may be maximum).
Abbreviation: E
Communicated by Gnaiger E 2011-02-27, edited 2014-04-23.
Level flow and State 3
- Level flow in mitochondrial respiration can define:
- (i) A state of (incompletely) coupled respiration at zero (minimum) phosphorylation potential (and saturating ADP and Pi) supported by an excess of defined reduced substrates, which is OXPHOS capacity, P, at minimum levels of ATP (to maintain the output force or Gibbs force of phosphorylation near zero);
- (ii) A state of noncoupled respiration at low mt-membrane potential supported by an excess of defined reduced substrates, which is ET capacity, E, defining the collapsed protonmotive force as (near-zero) output force (independent of ADP and ATP concentrations and the corresponding value of the Gibbs force of phosphorylation).
- Since E may be higher or equal to P, level flow does not sufficiently define a mitochondrial respiratory state, but refers only to the general boundary conditions of a low ouput force. State 3 is a state of ‘high ADP’ (Chance and Williams 1955), without restriction to ‘saturating ADP’. State 3 respiration, therefore, may be less than level flow, if limited by non-saturating ADP concentrations (State 3 respiration < P) or by the capacity of the phosphorylation system (State 3 respiration < E).
- » For comparison and references, see Static head.
Why not 'State 3u'?
- More details: »ET capacity
Electron transfer-pathway versus electron transport chain
- More details: »Electron-transfer-pathway state
Biochemical coupling efficiency: from 0 to <1
- More details: »Biochemical coupling efficiency
MitoPedia concepts:
Respiratory state,
Find,
Ergodynamics
MitoPedia topics:
EAGLE
