The background state, Y, is the non-activated or inhibited respiratory state at background flux, which is low in relation to the higher flux in the reference state, Z. The transition from the background state to the reference state is a step change. A metabolic control variable, X (substrate, activator), is added to the background state to stimulate flux to the level of the reference state. Alternatively, the metabolic control variable, X, is an inhibitor, which is present in the background state, Y, but absent in the reference state, Z. The background state is the baseline of a single step in the definition of the flux control factor. In a sequence of step changes, the common baseline state is the state of lowest flux in relation to all steps, which can be used as a baseline correction.
Reference: Flux control factor
MitoPedia topics: EAGLE
Communicated by Gnaiger E 2013-08-01; edited 2016-11-19.