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Difference between revisions of "State 3"

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|description=[[File:P.jpg |link=OXPHOS capacity]] '''State 3''' respiration is the ADP stimulated respiration of isolated coupled mitochondria in the presence of high ADP and [[Pi |P<sub>i</sub>]] concentrations, supported by a defined substrate or substrate combination at saturating oxygen levels [[Chance_1955_JBC-III|(Chance and Williams, 1955]]). State 3 respiration can also be induced in [[Permeabilized tissue or cells|permeabilized cells]], including permeabilized tissue preparations and tissue homogenates. ADP concentrations applied in State 3 are not necessarily saturating, whereas [[OXPHOS capacity]] is measured at saturating concentrations of ADP and P<sub>i</sub> (state ''P'').  For instance, non-saturating ADP concentrations are applied in State 3 in pulse titrations to determine the [[P/O ratio]] in State 3→4 (D→T) transitions, when saturating ADP concentrations would deplete the oxygen concentration in the closed oxygraph chamber before [[State 4]] is obtained ([[Gnaiger_2000_PNAS|Gnaiger et al 2000]]; [[Puchowicz_2004_Mitochondrion|Puchowicz et al 2004]]). Respiration in the OXPHOS state or in State 3 is partially [[coupled respiration|coupled]], and partially [[uncoupled respiration|uncoupled]] (physiological) or partially [[dyscoupled respiration|dyscoupled]] (pathological). A high [[mt-membrane potential]] provides the driving force for oxidative phosphorylation, to phosphorylate ADP to ATP and to transport ADP and ATP across the inner mt-membrane through the [[adenine nucleotide translocase]] (ANT). The mt-membrane potential is reduced, however, in comparison to the [[LEAK state]] of respiration, whereas the cytochromes are in a more oxidized [[redox state]].
|description=[[File:P.jpg |link=OXPHOS capacity]] '''State 3''' respiration is the ADP stimulated respiration of isolated coupled mitochondria in the presence of high ADP and [[Pi |P<sub>i</sub>]] concentrations, supported by a defined substrate or substrate combination at saturating oxygen levels [[Chance_1955_JBC-III|(Chance and Williams, 1955]]). State 3 respiration can also be induced in [[Permeabilized tissue or cells|permeabilized cells]], including permeabilized tissue preparations and tissue homogenates. ADP concentrations applied in State 3 are not necessarily saturating, whereas [[OXPHOS capacity]] is measured at saturating concentrations of ADP and P<sub>i</sub> (state ''P'').  For instance, non-saturating ADP concentrations are applied in State 3 in pulse titrations to determine the [[P/O ratio]] in State 3→4 (D→T) transitions, when saturating ADP concentrations would deplete the oxygen concentration in the closed oxygraph chamber before [[State 4]] is obtained ([[Gnaiger_2000_PNAS|Gnaiger et al 2000]]; [[Puchowicz_2004_Mitochondrion|Puchowicz et al 2004]]). Respiration in the OXPHOS state or in State 3 is partially [[coupled respiration|coupled]], and partially [[uncoupled respiration|uncoupled]] (physiological) or partially [[dyscoupled respiration|dyscoupled]] (pathological). A high [[mt-membrane potential]] provides the driving force for oxidative phosphorylation, to phosphorylate ADP to ATP and to transport ADP and ATP across the inner mt-membrane through the [[adenine nucleotide translocase]] (ANT). The mt-membrane potential is reduced, however, in comparison to the [[LEAK state]] of respiration, whereas the cytochromes are in a more oxidized [[redox state]].
|info=[[Chance 1955 JBC-III]], [[Gnaiger 2014 MitoPathways]]
|info=[[Chance 1955 JBC-III]], [[Gnaiger 2014 MitoPathways]]
|type=Respiration
}}
}}
{{MitoPedia concepts
{{MitoPedia concepts
|mitopedia concept=Respiratory state
|mitopedia concept=Respiratory state, Find
|type=Respiration
}}
{{MitoPedia methods|type=Respiration
}}
{{MitoPedia O2k and high-resolution respirometry|type=Respiration
}}
}}
{{MitoPedia topics
{{MitoPedia topics
|mitopedia topic=EAGLE
|mitopedia topic=EAGLE
}}
}}
Communicated by [[Gnaiger E]] 2010-08-15, edited 2014-06-23.
==Maximum oxygen flux in State 3 ?==
==Maximum oxygen flux in State 3 ?==
Oxygen flux is not necessarily 'maximum' in State 3 for different reasons:
Oxygen flux is not necessarily 'maximum' in State 3 for different reasons:

Revision as of 10:52, 19 November 2016


high-resolution terminology - matching measurements at high-resolution


State 3

Description

P.jpg State 3 respiration is the ADP stimulated respiration of isolated coupled mitochondria in the presence of high ADP and Pi concentrations, supported by a defined substrate or substrate combination at saturating oxygen levels (Chance and Williams, 1955). State 3 respiration can also be induced in permeabilized cells, including permeabilized tissue preparations and tissue homogenates. ADP concentrations applied in State 3 are not necessarily saturating, whereas OXPHOS capacity is measured at saturating concentrations of ADP and Pi (state P). For instance, non-saturating ADP concentrations are applied in State 3 in pulse titrations to determine the P/O ratio in State 3→4 (D→T) transitions, when saturating ADP concentrations would deplete the oxygen concentration in the closed oxygraph chamber before State 4 is obtained (Gnaiger et al 2000; Puchowicz et al 2004). Respiration in the OXPHOS state or in State 3 is partially coupled, and partially uncoupled (physiological) or partially dyscoupled (pathological). A high mt-membrane potential provides the driving force for oxidative phosphorylation, to phosphorylate ADP to ATP and to transport ADP and ATP across the inner mt-membrane through the adenine nucleotide translocase (ANT). The mt-membrane potential is reduced, however, in comparison to the LEAK state of respiration, whereas the cytochromes are in a more oxidized redox state.

Abbreviation: P

Reference: Chance 1955 JBC-III, Gnaiger 2014 MitoPathways


MitoPedia concepts: Respiratory state, Find 


MitoPedia topics: EAGLE 

Communicated by Gnaiger E 2010-08-15, edited 2014-06-23.

Maximum oxygen flux in State 3 ?

Oxygen flux is not necessarily 'maximum' in State 3 for different reasons:

  • Concentrations of ADP and inorganic phosphate (Pi) are high but may not be saturating (kinetic limitation).
  • The substrate or substrate combination may not support the physiological maximum flux through the electron transfer system (ETS), particularly due to electron gating of mitochondrial pathways converging at the Q-junction (limitation due to substrate control).
  • OXPHOS capacity is less than ETS capacity in coupled mitochondria with limiting phosphorylation system capacity (limitation by the enzymatic capacity of utilizating the electrochemical proton gradient).