- high-resolution terminology - matching measurements at high-resolution
F-junction
Description
The F-junction is a junction for convergent electron flow in the electron transfer system (ETS) from fatty acids through fatty acyl CoA dehydrogenase (reduced form FADH2) to electron transferring flavoprotein (CETF), and further transfer through the Q-junction to Complex III (CIII). The concept of the F-junction and N-junction provides a basis for defining categories of SUIT protocols. Fatty acid oxidation, in the F-pathway control state, not only depends on electron transfer through the F-junction (which is typically rate-limiting) but simultaneously generates NADH and thus depends on N-junction throughput. Hence FAO can be inhibited completely by inhibition of Complex I (CI). In addition and independent of this source of NADH, the N-junction substrate malate is required as a co-substrate for FAO in mt-preparations, since accumulation of AcetylCoA inhibits FAO in the absence of malate. Malate is oxidized in a reaction catalyzed by malate dehydrogenase to oxaloacetate (yielding NADH), which then stimulates the entry of AcetylCoA into the TCA cycle catalyzed by citrate synthase.
Reference: Gnaiger 2014 MitoPathways
MitoPedia concepts:
MiP concept,
SUIT concept
MitoPedia methods:
Respirometry
Communicated by Gnaiger E 2016-02-12, edited 2016-11-08.
