Description
The Q-junction is a junction for convergent electron flow in the Electron transfer-pathway (ET-pathway) 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 Complex IV (CIV). The concept of the Q-junction, with the N-junction and F-junction upstream, provides the rationale for defining Electron transfer-pathway 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.
- Β» Keywords
- Specific
- General
- Β» Categories of SUIT protocols
- Β» Choline dehydrogenase
- Β» Complex I
- Β» Complex II
- Β» Dihydro-orotate dehydrogenase
- Β» Electron-transferring flavoprotein complex
- Β» Electron transfer-pathway
- Β» F-junction
- Β» Glycerophosphate dehydrogenase complex
- Β» N-junction
- Β» NS-linked electron flow
- Β» Electron transfer-pathway states
- General
Related MitoPedia pages
- Electron transfer-pathway, ET-pathway
- Electron transfer-pathway state
- Coupling control state E