Difference between revisions of "Level flow"
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|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). | |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). | ||
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{{MitoPedia methods | |||
|mitopedia method=Respirometry | |||
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{{MitoPedia topics | {{MitoPedia topics | ||
Revision as of 19:53, 15 November 2011
- 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).
MitoPedia methods:
Respirometry
MitoPedia topics: "Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property.
Respiratory state"Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property.
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 non-coupled respiration at collapsed mt-membrane potential supported by an excess of defined reduced substrates, which is ETS 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 zero 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.
