Difference between revisions of "F-junction"
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|description=[[File:SUIT-catg F.jpg|right|300px|F-junction]] | |description=[[File:SUIT-catg F.jpg|right|300px|F-junction]] | ||
The '''F-junction''' is a junction for [[convergent electron flow]] in the [[electron transfer pathway]] (ET-pathway) 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. | The '''F-junction''' is a junction for [[convergent electron flow]] in the [[electron transfer pathway]] (ET-pathway) 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. | ||
|info=[[Gnaiger | |info=[[Gnaiger 2020 BEC MitoPathways]] | ||
}} | }} | ||
Communicated by [[Gnaiger E]] 2016-02-12, edited 2016-11-08. | |||
{{MitoPedia concepts | {{MitoPedia concepts | ||
|mitopedia concept=MiP concept, SUIT concept | |mitopedia concept=MiP concept, SUIT concept | ||
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|mitopedia method=Respirometry | |mitopedia method=Respirometry | ||
}} | }} | ||
Revision as of 20:10, 1 January 2021
Description
The F-junction is a junction for convergent electron flow in the electron transfer pathway (ET-pathway) 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 2020 BEC MitoPathways
Communicated by Gnaiger E 2016-02-12, edited 2016-11-08.
MitoPedia concepts:
MiP concept,
SUIT concept
MitoPedia methods:
Respirometry