Difference between revisions of "F-junction"
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The '''F-junction''' is a junction for [[convergent electron flow]] in the [[electron transfer system]] (ETS) from fatty acids ([[ETS substrate types |type F substrates]]) 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 (the [[FAO]] substrate 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 type N substrate malate is required as a co-substrate for FAO in mt-preparations, since accumulation of AcetylCo 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 AcetylCo into the TCA cycle catalyzed by citrate synthase. | The '''F-junction''' is a junction for [[convergent electron flow]] in the [[electron transfer system]] (ETS) from fatty acids ([[ETS substrate types |type F substrates]]) 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 (the [[FAO]] substrate 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 type N substrate malate is required as a co-substrate for FAO in mt-preparations, since accumulation of AcetylCo 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 AcetylCo into the TCA cycle catalyzed by citrate synthase. | ||
|info=[[Gnaiger 2014 MitoPathways]] | |info=[[Gnaiger 2014 MitoPathways]] | ||
}} | |||
{{MitoPedia concepts | |||
|mitopedia concept=MiP concept, SUIT concept | |||
}} | }} | ||
{{MitoPedia methods | {{MitoPedia methods | ||
|mitopedia method=Respirometry | |mitopedia method=Respirometry | ||
}} | }} | ||
{{MitoPedia O2k and high-resolution respirometry | {{MitoPedia O2k and high-resolution respirometry}} | ||
{{MitoPedia topics}} | |||
}} | Contributed by [[Gnaiger E]] 2016-02-12 | ||
Revision as of 16:41, 13 May 2016
- 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 (type F substrates) 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 (the FAO substrate 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 type N substrate malate is required as a co-substrate for FAO in mt-preparations, since accumulation of AcetylCo 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 AcetylCo into the TCA cycle catalyzed by citrate synthase.
Reference: Gnaiger 2014 MitoPathways
MitoPedia concepts:
MiP concept,
SUIT concept
MitoPedia methods:
Respirometry
Contributed by Gnaiger E 2016-02-12
