Difference between revisions of "Pathway control ratio"
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Careful selection of the reference state, ''J''<sub>ref</sub>, is required, for which some guidelines may be provided without the possibility to formulate general rules. ''FCR'' are best defined by taking ''J''<sub>ref</sub> as the maximum flux (e.g. [[Additive effect of convergent CI+II electron flow|CI<small>&</small>II]]<sub>''[[ETS|E]]''</sub>), such that flux in various other respiratory states, ''J<sub>i</sub>'', smaller or equal to ''J''<sub>ref</sub>. However, this is not generally possible with ''SCR''. For instance, the CI/CII substrate control ratio (at constant coupling state) may be larger or smaller than 1.0, depending on the mitochondrial source and various mitochondrial injuries. CII-linked respiration may be selected preferentially as ''J''<sub>ref</sub>, if mitochondria with variable CI-linked injuries are studied. In contrast, the [[reference state]], ''Z'', is strictly defined for [[flux control factor]]s. | Careful selection of the reference state, ''J''<sub>ref</sub>, is required, for which some guidelines may be provided without the possibility to formulate general rules. ''FCR'' are best defined by taking ''J''<sub>ref</sub> as the maximum flux (e.g. [[Additive effect of convergent CI+II electron flow|CI<small>&</small>II]]<sub>''[[ETS|E]]''</sub>), such that flux in various other respiratory states, ''J<sub>i</sub>'', smaller or equal to ''J''<sub>ref</sub>. However, this is not generally possible with ''SCR''. For instance, the CI/CII substrate control ratio (at constant coupling state) may be larger or smaller than 1.0, depending on the mitochondrial source and various mitochondrial injuries. CII-linked respiration may be selected preferentially as ''J''<sub>ref</sub>, if mitochondria with variable CI-linked injuries are studied. In contrast, the [[reference state]], ''Z'', is strictly defined for [[flux control factor]]s. | ||
|info=[[Gnaiger 2009 Int J Biochem Cell Biol]]; [[MitoPedia: Respiratory states]] | |info=[[Gnaiger 2009 Int J Biochem Cell Biol]]; [[MitoPedia: Respiratory states]] | ||
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{{MitoPedia concepts | |||
|mitopedia concept=Respiratory control ratio | |||
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{{MitoPedia methods | {{MitoPedia methods | ||
|mitopedia method=Respirometry | |mitopedia method=Respirometry | ||
}} | }} | ||
{{MitoPedia topics | {{MitoPedia O2k and high-resolution respirometry}} | ||
{{MitoPedia topics}} | |||
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Revision as of 14:09, 8 February 2016
Description
Substrate control ratios, SCR, are flux control ratios, FCR, at a constant mitochondrial coupling state. Whereas there are only three well-defined coupling states of mitochondrial respiration, L, P, E (LEAK, OXPHOS, ETS), numerous substrate states are possible.
Careful selection of the reference state, Jref, is required, for which some guidelines may be provided without the possibility to formulate general rules. FCR are best defined by taking Jref as the maximum flux (e.g. CI&IIE), such that flux in various other respiratory states, Ji, smaller or equal to Jref. However, this is not generally possible with SCR. For instance, the CI/CII substrate control ratio (at constant coupling state) may be larger or smaller than 1.0, depending on the mitochondrial source and various mitochondrial injuries. CII-linked respiration may be selected preferentially as Jref, if mitochondria with variable CI-linked injuries are studied. In contrast, the reference state, Z, is strictly defined for flux control factors.
Abbreviation: SCR
Reference: Gnaiger 2009 Int J Biochem Cell Biol; MitoPedia: Respiratory states
MitoPedia concepts:
Respiratory control ratio
MitoPedia methods:
Respirometry