Description
The Q-junction is a junction for convergent electron flow in the electron transfer system (ETS) from type N substrates and mt-matix dehydrogenases through Complex I (CI), from type F substrates and FA oxidation through electron-transferring flavoprotein complex (CETF), from succinate (S) through Complex II (CII), from glycoreophosphate (Gp) through glycerophosphate dehydrogenase complex (CGpDH), from choline through choline dehydrogenase, from dihydro-orotate through dihydro-orotate dehydrogenase, and other enzyme complexes into the Q-cycle (ubiquinol/ubiquinone), and further downstream to Complex III (CIII) and CIV. The concept of the Q-junction, with the N-junction and F-junction upstream, provides the rationale for defining pathway control states and categories of SUIT protocols.
Reference: Gnaiger 2009 Int J Biochem Cell Biol, Gnaiger 2014 MitoPathways
MitoPedia concepts:
MiP concept,
SUIT concept
MitoPedia methods:
Respirometry
MitoPedia topics:
Enzyme
Contributed by Gnaiger E 2010-08-15; edited 2016-02-12, 2016-03-28.
- Convergent NS-linked electron flow at the Q-junction, exerting an additive effect on flux, versus electron gaiting for separation of single N- and S-input pathways (upper panel: Gnaiger 2009; lower panel: Hatefi 1962 J Biol Chem-XLII). Modified Fig. 1.5 in Gnaiger 2014 MitoPathways.
- » Keywords
- » Categories of SUIT protocols
- » Choline dehydrogenase
- » Complex I
- » Complex II
- » Complex III
- » Convergent electron flow
- » Dihydro-orotate dehydrogenase
- » Electron-transferring flavoprotein complex
- » Electron transfer system
- » F-junction
- » Glycerophosphate dehydrogenase complex
- » N-junction
- » Pathway control states
Related MitoPedia pages
- Electron transfer system, ETS
- Pathway control states
- Coupling control state E