Pathway control ratio
{{MitoPedia |abbr=SCR |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. [[Additive effect of convergent NS-electron flow|NSE), 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 N/S substrate control ratio (at constant coupling state) may be larger or smaller than 1.0, depending on the mitochondrial source and various mitochondrial injuries. S-linked respiration may be selected preferentially as Jref, if mitochondria with variable injuries of N-linked respiration are studied. In contrast, the reference state, Z, is strictly defined for flux control factors. |info=Gnaiger 2009 Int J Biochem Cell Biol; MitoPedia: Respiratory states }}
MitoPedia concepts: Respiratory control ratio
MitoPedia methods:
Respirometry
