Difference between revisions of "F-junction"

Revision as of 20:39, 9 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 methods: Respirometry

MitoPedia O2k and high-resolution respirometry: "SUIT protocol" is not in the list (O2k hardware, DatLab, Oroboros QM, O2k-Open Support, O2k-Respirometry, O2k-FluoRespirometry) of allowed values for the "MitoPedia O2k and high-resolution respirometry" property. SUIT protocol"SUIT protocol" is not in the list (O2k hardware, DatLab, Oroboros QM, O2k-Open Support, O2k-Respirometry, O2k-FluoRespirometry) of allowed values for the "MitoPedia O2k and high-resolution respirometry" property.

Contributed by Gnaiger E 2016-02-12

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 {{MitoPedia
 |description=[[File:SUIT-Catg NF.jpg|right|300px|F-junction]]
-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 (FAO) 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]]
 }}