Difference between revisions of "Electron transfer pathway"

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high-resolution terminology - matching measurements at high-resolution

Electron transfer pathway

Description

The mitochondrial electron transfer system (ETS; synonymous with 'electron transport system') transfers electrons from externally supplied reduced substrates to oxygen. It consists of the membrane-bound ETS (mETS) with enzyme complexes located in the inner mt-membrane, mt-matrix dehydrogenases generating NADH, and the transport systems involved in metabolite exchange across the mt-membranes (see ETS capacity).

Abbreviation: ETS

Reference: Gnaiger 2009 Int J Biochem Cell Biol

MitoPedia methods: Respirometry

MitoPedia topics: "Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property. Respiratory state"Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property.

Why ETS, why not State 3u?

» ETS capacity

Related terms in Bioblast

OXPHOS, P

ETS, E

ROUTINE, R

LEAK, L

ROX, R

@@ Line 1: / Line 1: @@
 {{MitoPedia
 |abbr=ETS
-|description=[[File:E.jpg |link=ETS capacity]] The mitochondrial '''electron transfer system''' (ETS; synonymous with 'electron transport system') transfers electrons from externally supplied reduced substrates to oxygen.  It consists of the [[membrane-bound ETS|membrane-bound ETS (mETS)]] with enzyme complexes located in the inner [[mt-membrane]], mt-matrix dehydrogenases generating NADH, and the transport systems involved in metabolite exchange across the mt-membranes (see [[ETS capacity]]). [[Electron_transfer_system#Electron_transfer_system_versus_electron_transport_chain |» '''MiPNet article''']]
+|description=[[File:E.jpg |link=ETS capacity]] The mitochondrial '''electron transfer system''' (ETS; synonymous with 'electron transport system') transfers electrons from externally supplied reduced substrates to oxygen.  It consists of the [[membrane-bound ETS|membrane-bound ETS (mETS)]] with enzyme complexes located in the inner [[mt-membrane]], mt-matrix dehydrogenases generating NADH, and the transport systems involved in metabolite exchange across the mt-membranes (see [[ETS capacity]]).
 |info=[[Gnaiger 2009 Int J Biochem Cell Biol]]
 |type=Respiration
@@ Line 13: / Line 13: @@
 |type=Respiration
 }}
-__TOC__
+== Why ETS, why not State 3u? ==
-[[File:Hatefi 1962 CI+II 2012.jpg|right|500px|Q-junction]]
+» [[ETS capacity]]
-= Electron transfer system versus electron transport chain =
-{{Publication
-|title=Gnaiger E (2014) Electron transfer system versus electron transport chain. Mitochondr Physiol Network 2014-07-06.
-|info=[[Gnaiger 2012 MitoPathways]]
-|authors=OROBOROS
-|year=2014-07-06
-|journal=MiPNet
-|abstract=The well established terms 'respiratory chain' or 'electron transfer chain' suggest erroneously that the convergent '''electron transfer system''' may be designed as a simple ''chain''.
-|mipnetlab=AT Innsbruck Gnaiger E
-}}
-{{Labeling
-|couplingstates=ETS
-|instruments=Theory
-}}
-== Electron transfer system versus chain ==
-The term '''electron transport chain''' (or electron transfer chain, ETC) is a misnomer. Understanding mitochondrial respiratory control has suffered greatly from this inappropriate terminology, although textbooks using the term ETC (Lehninger 1970) make it sufficiently clear that '''electron transfer systems are not arranged as a chain''': the „ETC‟ is in fact not a simple chain but an arrangement of electron transfer complexes in a non-linear, convergent electron transfer system. The classically introduced term '''electron transfer system''' (Hatefi et al 1962 <ref> Hatefi Y, Haavik AG, Fowler LR, Griffiths DE (1962) Studies on the '''electron transfer system''' XLII. Reconstitution of the electron transfer system. J Biol Chem 237: 2661-2669. [[Hatefi 1962 J Biol Chem-XLII |»Open Access]]</ref>) is accurate and sufficient. <ref> International Union of Biochemistry (1991) Nomenclature of '''electron-transfer proteins.''' Biochim Biophys Acta 1060. [http://www.chem.qmul.ac.uk/iubmb/etp/ »Open Access]</ref>
-The established convention of defining the 'electron transport chain' as being comprised of four Complexes has conceptual weaknesses.
-(a) In fact, there are at least six Complexes of mitochondrial electron transfer: In addition to Complexes I and II, [[Glycerophosphate_dehydrogenase|glycerophosphate dehydrogenase]] (GpDH) and [[Electron-transferring_flavoprotein|electron transferring flavoprotein]] (ETF) are involved in the [[Q-junction]] with electron transfer to [[Complex III]].
-<ref>International Union of Biochemistry (1991) Nomenclature of '''electron-transfer proteins.''' Biochim Biophys Acta 1060. [http://www.chem.qmul.ac.uk/iubmb/etp/ »Open Access]</ref>,<ref>Gnaiger E (2012) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 3rd ed. Mitochondr Physiol Network 17.18. OROBOROS MiPNet Publications, Innsbruck: 64 pp. [[Gnaiger_2012_MitoPathways |»Open Access]]</ref>
-(b) The term „chain‟ suggests a linear sequence, whereas the functional structure of the electron transfer system can only be understood by recognizing '''the convergence of electron flow at the Q-junction''', followed by a chain of Complexes III and IV, mediated by [[cytochrome c | cytochrome ''c'']]. <ref> Gnaiger E (2012) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 3rd ed. Mitochondr Physiol Network 17.18. OROBOROS MiPNet Publications, Innsbruck: 64 pp. [[Gnaiger_2012_MitoPathways |»Open Access]]</ref>
-Electrons flow to oxygen from either [[Complex I]] with a total of three coupling sites, or from [[Complex II]] and other flavoproteins, providing multiple entries into the Q-cycle with two coupling sites downstream. <ref> Gnaiger E (2012) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 3rd ed. Mitochondr Physiol Network 17.18. OROBOROS MiPNet Publications, Innsbruck: 64 pp. [[Gnaiger_2012_MitoPathways |»Open Access]]</ref>
-== Electron transfer versus transport ==
-Electron transfer and electron transport are used synonymously. A general distinction, however, may be helpful:
-(i) '''Transfer''' (inter- or intramolecular) of a reactant involves a chemical reaction.
-(ii) '''Transport''' (from one place to another) of an entity is a (vectorial) process in contrast to a chemical reaction.
-<ref> International Union of Biochemistry and Molecular Biology. Recommendations for terminology and databases for biochemical thermodynamics - The IUPAC Green Book [http://www.chem.qmul.ac.uk/iubmb/thermod2/ »Open Access].</ref>
 == Related terms in Bioblast ==
@@ Line 64: / Line 27: @@
 [[File:ROX.jpg |link=Residual oxygen consumption]] [[Residual oxygen consumption |ROX]], ''R''
-=== The ETS state ===
-* [[ETS capacity]] - [[State 3u]]<ref>Gnaiger E. Why not State 3u? Mitochondr Physiol Network. »[[ETS capacity]]</ref>
-* [[ETS-competent substrate state]]
-* [[Level flow]]
-* [[Noncoupled respiration]] - [[Uncoupler]]<ref>Gnaiger E. Is respiration uncoupled - noncoupled - dyscoupled? Mitochondr Physiol Network. »[[Uncoupler]]</ref>
-* [[Phosphorylation control protocol]]
-=== ETS-related flux control factors ===
-* [[Biochemical coupling efficiency]]<ref>Gnaiger E. Biochemical coupling efficiency: from 0 to <1. Mitochondr Physiol Network. »[[Biochemical coupling efficiency]]</ref>
-* [[E-L coupling control factor]] - [[E-P coupling control factor]] - [[E-R coupling control factor]]
-=== ETS-related flux control ratios ===
-* [[Coupling control ratio]] - [[Uncoupling control ratio]]
-* [[LEAK control ratio per E]] - [[Phosphorylation system control ratio]]
-* [[ROUTINE control ratio]] - [[NetROUTINE control ratio]]
-== References ==
-<references/>