Respiratory electron transport, ATP synthesis by chemiosmotic coupling, and heat production by uncoupling proteins. (Homo sapiens)

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1, 2141, 21, 21, 21, 23, 6, 9144, 5, 7, 8, 10...11, 1314UCP [mitochondrialinner membrane]mitochondrial intermembrane spaceDr.97370FA anion:UCP dimer "head-out" complex[mitochondrial innermembrane]UCP [mitochondrialinner membrane]UCP [mitochondrialinner membrane]FA anion:UCP dimer"head-in" complex[mitochondrial innermembrane]UCP dimer[mitochondrial innermembrane]Complex III -cytochrome c1-hemecomplex[mitochondrial innermembrane]UCP dimer[mitochondrial innermembrane]Complex I - 20 kDasubunit-4Fe-4Scluster complex[mitochondrial innermembrane]ATPase CF(0)[mitochondrial innermembrane]IP sub-complex[mitochondrial innermembrane]Succinatedehydrogenase IronSulphur (subunit B)[mitochondrial innermembrane]Succinatedehydrogenasecomplex (reduced)[mitochondrial innermembrane]ATPase CF(0)[mitochondrial innermembrane]Complex III - Rieskeprotein-2Fe-2Scluster complex[mitochondrial innermembrane]ATPase complex[mitochondrial innermembrane]ATPase CF(1)[mitochondrialmatrix]UCP dimer[mitochondrial innermembrane]ETF [mitochondrialmatrix]Complex I - 23 kDasubunit-2 x 4Fe-4Scluster complex[mitochondrial innermembrane]Cytochrome c oxidase[mitochondrial innermembrane]mitochondrial matrixComplex I -NADH:Ubiquinoneoxidoreductase[mitochondrial innermembrane]Cytochrome c(oxidized)[mitochondrial innermembrane]FP sub-complex[mitochondrial innermembrane]Complex I - 49 kDasubunit-4Fe-4Scluster complex[mitochondrial innermembrane]Dr.97370HP subcomplex[mitochondrial innermembrane]Succinatedehydrogenase IronSulphur (subunit B)[mitochondrial innermembrane]ATPase complex[mitochondrial innermembrane]Complex I - 39 kDasubunit-FAD cofactor[mitochondrial innermembrane]Succinatedehydrogenaseflavoprotein(subunit A),oxidised[mitochondrial innermembrane]Succinatedehydrogenaseflavoprotein(subunit A)[mitochondrial innermembrane]UCP dimer[mitochondrial innermembrane]Complex IV -Cytochrome c oxidasesubunit 2-Cu complex[mitochondrial innermembrane]Ubiquinol-cytochromec reductase[mitochondrial innermembrane]ATPase CF(1)[mitochondrialmatrix]cytochrome b-hemecomplex[mitochondrial innermembrane]Cytochrome c(reduced)[mitochondrial innermembrane]ATPase CF(1)[mitochondrialmatrix]Complex I - 42 kDasubunit-FAD cofactor[mitochondrial innermembrane]UCP [mitochondrialinner membrane]ATPase CF(0)[mitochondrial innermembrane]Complex I - 51 kDasubunit-FMN-4Fe-4Scluster complex[mitochondrial innermembrane]ATPase complex[mitochondrial innermembrane]ETF (reduced)[mitochondrialmatrix]ATPase-ADP and Picomplex[mitochondrial innermembrane]Complex I - 75 kDasubunit-2Fe-2Scluster-4Fe- 2 x 4Scluster complex[mitochondrial innermembrane]ATPase-ATP complex[mitochondrial innermembrane]Dr.97370Succinatedehydrogenasecomplex (oxidised)[mitochondrial innermembrane]Fatty Acid "head-in"COX7A2L[mitochondrial innermembrane]MT-CYB[mitochondrial innermembrane]SDHA [mitochondrialinner membrane]ATP5E [mitochondrialmatrix]NDUFS8[mitochondrial innermembrane]ATP5O [mitochondrialinner membrane]MT-ATP8[mitochondrial innermembrane]NDUFB5[mitochondrial innermembrane]UCP3 [mitochondrialinner membrane]NDUFS3[mitochondrial innermembrane]NDUFAB1[mitochondrial innermembrane]FADH2ATP [mitochondrialmatrix]NDUFA9[mitochondrial innermembrane]NDUFB8[mitochondrial innermembrane]H+Fatty Acid anion"head-in"ATP5B [mitochondrialmatrix]Succinatedehydrogenasecomplex (oxidised)UCP dimerUQCRQ [mitochondrialinner membrane]NDUFA2[mitochondrial innermembrane]ATP5J2[mitochondrial innermembrane]COX5A [mitochondrialinner membrane]Homologues ofFGA(20-866)NDUFV3[mitochondrial innermembrane]NDUFC1[mitochondrial innermembrane]NDUFB6[mitochondrial innermembrane]NDUFV2[mitochondrial innermembrane]ATP5A1[mitochondrialmatrix]ATP5I [mitochondrialinner membrane]A_15_P101542MT-ND3[mitochondrial innermembrane]NDUFS7[mitochondrial innermembrane]NDUFB10(2-172)[mitochondrial innermembrane]FMN [mitochondrialinner membrane]NADHCytochrome c oxidaseATP5I [mitochondrialinner membrane]UCP2 [mitochondrialinner membrane]NDUFA3(1-84)[mitochondrial innermembrane]NDUFB11[mitochondrial innermembrane]FAD [mitochondrialinner membrane]MT-ND6[mitochondrial innermembrane]ATP5H [mitochondrialinner membrane]NDUFA13[mitochondrial innermembrane]factor X heavy chain[extracellularregion]QH2ATP5L [mitochondrialinner membrane]UCP2 [mitochondrialinner membrane]NDUFA8[mitochondrial innermembrane]QH2ATP5J [mitochondrialinner membrane]MT-ND5[mitochondrial innermembrane]NDUFA11[mitochondrial innermembrane]COX6B1[mitochondrial innermembrane]AMP [mitochondrialmatrix]Homologues ofFGA(20-866)ATP5A1[mitochondrialmatrix]ATP5E [mitochondrialmatrix]H+Cytochrome c(reduced)NDUFB3[mitochondrial innermembrane]ATP5B [mitochondrialmatrix]ATPase-ATP complexNDUFS1[mitochondrial innermembrane]MT-ATP6[mitochondrial innermembrane]ATP5O [mitochondrialinner membrane]ATP5F1[mitochondrial innermembrane]NDUFB7[mitochondrial innermembrane]UQCRFS1(79-274)[mitochondrial innermembrane]Cytochrome c(oxidized)MT-CO2[mitochondrial innermembrane]Fatty Acid anion"head-in"[mitochondrial innermembrane]UQCRC2[mitochondrial innermembrane]MT-ND4L[mitochondrial innermembrane]NDUFS5[mitochondrial innermembrane]SDHD [mitochondrialinner membrane]COX7B [mitochondrialinner membrane]MT-CO1[mitochondrial innermembrane]NDUFB4[mitochondrial innermembrane]H2OATP5O [mitochondrialinner membrane]NDUFA10[mitochondrial innermembrane]Pifactor X heavy chain[extracellularregion]NDUFA6[mitochondrial innermembrane]ADPSDHC [mitochondrialinner membrane]UCP1(1-307)[mitochondrial innermembrane]CYCS [mitochondrialinner membrane]ATPase complexCoQMT-ATP8[mitochondrial innermembrane]MT-ND4[mitochondrial innermembrane]NDUFB2[mitochondrial innermembrane]FADETFB [mitochondrialmatrix]ATP5J2[mitochondrial innermembrane]SDHC [mitochondrialinner membrane]UCP1(1-307)[mitochondrial innermembrane]ATPase-ADP and PicomplexCOX6C(3-75)[mitochondrial innermembrane]NDUFA1[mitochondrial innermembrane]Fatty Acid anion"head-out"[mitochondrial innermembrane]Fatty Acid"head-out"ATP5D [mitochondrialmatrix]UCP3 [mitochondrialinner membrane]NAD+ATP5G1[mitochondrial innermembrane]Homologues ofFGA(20-866)ATP5J [mitochondrialinner membrane]FA anion:UCP dimer"head-in" complexMT-ATP6[mitochondrial innermembrane]NDUFC2[mitochondrial innermembrane]NDUFA5[mitochondrial innermembrane]NDUFB9[mitochondrial innermembrane]CYC1 [mitochondrialinner membrane]ATP5L [mitochondrialinner membrane]UCP1(1-307)[mitochondrial innermembrane]ATP5C1[mitochondrialmatrix]NDUFV1[mitochondrial innermembrane]Pi [mitochondrialmatrix]Long-chain fattyacidATP5C1[mitochondrialmatrix]UQCRB [mitochondrialinner membrane]ATP5A1[mitochondrialmatrix]UCP3 [mitochondrialinner membrane]COX5B [mitochondrialinner membrane]UCP dimerUCP3 [mitochondrialinner membrane]COX8A [mitochondrialinner membrane]SDHB [mitochondrialinner membrane]UCP2 [mitochondrialinner membrane]ADP [mitochondrialmatrix]Purine nucleotideCuA [mitochondrialinner membrane]Complex I -NADH:UbiquinoneoxidoreductaseATPSuccinatedehydrogenasecomplex (reduced)COX4I1[mitochondrial innermembrane]ferriheme[mitochondrial innermembrane]ATP5D [mitochondrialmatrix]ETFA(1-?)[mitochondrialmatrix]ATP5I [mitochondrialinner membrane]ATP5H [mitochondrialinner membrane]COX7C [mitochondrialinner membrane]H2OMT-ATP6[mitochondrial innermembrane]NDUFS4[mitochondrial innermembrane]MT-ND2[mitochondrial innermembrane]ATP5F1[mitochondrial innermembrane]ATP5H [mitochondrialinner membrane]ETFDHATP5C1[mitochondrialmatrix]ATP5E [mitochondrialmatrix]ETFA(1-?)[mitochondrialmatrix]SDHA [mitochondrialinner membrane]UQCR11[mitochondrial innermembrane]UQCRH [mitochondrialinner membrane]Ubiquinol-cytochromec reductaseATP5B [mitochondrialmatrix]AMP [mitochondrialmatrix]CoQSDHD [mitochondrialinner membrane]ATP5G1[mitochondrial innermembrane]MT-CO3(1-261)[mitochondrial innermembrane]ETFB [mitochondrialmatrix]UQCR10[mitochondrial innermembrane]MT-ATP8[mitochondrial innermembrane]NDUFA12[mitochondrial innermembrane]FADH2 [mitochondrialinner membrane]ferroheme[mitochondrial innermembrane]ETFFADH2 [mitochondrialmatrix]UQCRC1[mitochondrial innermembrane]NDUFS2[mitochondrial innermembrane]FAD [mitochondrialmatrix]FAD [mitochondrialinner membrane]factor X heavy chain[extracellularregion]FA anion:UCP dimer "head-out" complexSDHB [mitochondrialinner membrane]ATP5G1[mitochondrial innermembrane]NDUFA4[mitochondrial innermembrane]UCP1(1-307)[mitochondrial innermembrane]A_15_P101542ETF (reduced)QH2UCP2 [mitochondrialinner membrane]ATP5L [mitochondrialinner membrane]A_15_P101542ATP5J2[mitochondrial innermembrane]Fatty Acid anion"head-out"ATP5F1[mitochondrial innermembrane]O2MT-ND1[mitochondrial innermembrane]NDUFB1[mitochondrial innermembrane]COX6A1[mitochondrial innermembrane]NDUFA7[mitochondrial innermembrane]ATP5J [mitochondrialinner membrane]CYCS [mitochondrialinner membrane]ATP5D [mitochondrialmatrix]NDUFS6[mitochondrial innermembrane]


Description

Oxidation of fatty acids and pyruvate in the mitochondrial matrix yield large amounts of NADH. The respiratory electron transport chain couples the re-oxidation of this NADH to NAD+ to the export of protons from the mitochonrial matrix, generating a chemiosmotic gradient across the inner mitochondrial membrane. This gradient is used to drive the synthesis of ATP; it can also be bypassed by uncoupling proteins to generate heat, a reaction in brown fat that may be important in regulation of body temperature in newborn children.Original Pathway at Reactome: http://www.reactome.org/PathwayBrowser/#DB=gk_current&FOCUS_SPECIES_ID=48887&FOCUS_PATHWAY_ID=163200

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Bibliography

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History

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CompareRevisionActionTimeUserComment
114966view16:49, 25 January 2021ReactomeTeamReactome version 75
113410view11:48, 2 November 2020ReactomeTeamReactome version 74
112612view15:59, 9 October 2020ReactomeTeamReactome version 73
101528view11:39, 1 November 2018ReactomeTeamreactome version 66
101063view21:21, 31 October 2018ReactomeTeamreactome version 65
100594view19:55, 31 October 2018ReactomeTeamreactome version 64
100143view16:40, 31 October 2018ReactomeTeamreactome version 63
99693view15:09, 31 October 2018ReactomeTeamreactome version 62 (2nd attempt)
99281view12:45, 31 October 2018ReactomeTeamreactome version 62
93907view13:44, 16 August 2017ReactomeTeamreactome version 61
93481view11:24, 9 August 2017ReactomeTeamreactome version 61
86578view09:21, 11 July 2016ReactomeTeamreactome version 56
83426view11:11, 18 November 2015ReactomeTeamVersion54
81630view13:10, 21 August 2015ReactomeTeamVersion53
77091view08:38, 17 July 2014ReactomeTeamFixed remaining interactions
76797view12:18, 16 July 2014ReactomeTeamFixed remaining interactions
76120view10:18, 11 June 2014ReactomeTeamRe-fixing comment source
75832view11:40, 10 June 2014ReactomeTeamReactome 48 Update
75192view09:40, 9 May 2014AnweshaFixing comment source for displaying WikiPathways description
74837view10:06, 30 April 2014ReactomeTeamReactome46
74431view07:10, 19 April 2014EgonwRelocated an InfoBox.
68937view17:34, 8 July 2013MaintBotUpdated to 2013 gpml schema
45047view19:09, 6 October 2011ThomasOntology Term : 'energy metabolic pathway' added !
42118view21:58, 4 March 2011MaintBotAutomatic update
39928view05:56, 21 January 2011MaintBotNew pathway

External references

DataNodes

View all...
NameTypeDatabase referenceComment
ADP [mitochondrial matrix]MetaboliteCHEBI:16761 (ChEBI)
ADPMetaboliteCHEBI:16761 (ChEBI)
AMP [mitochondrial matrix]MetaboliteCHEBI:16027 (ChEBI)
ATP [mitochondrial matrix]MetaboliteCHEBI:15422 (ChEBI)
ATP5A1

[mitochondrial

matrix]		ProteinP25705 (Uniprot-TrEMBL)
ATP5B [mitochondrial matrix]ProteinP06576 (Uniprot-TrEMBL)
ATP5C1

[mitochondrial

matrix]		ProteinP36542 (Uniprot-TrEMBL)
ATP5D [mitochondrial matrix]ProteinP30049 (Uniprot-TrEMBL)
ATP5E [mitochondrial matrix]ProteinP56381 (Uniprot-TrEMBL)
ATP5F1

[mitochondrial inner

membrane]		ProteinP24539 (Uniprot-TrEMBL)
ATP5G1

[mitochondrial inner

membrane]		ProteinP05496 (Uniprot-TrEMBL)
ATP5H [mitochondrial inner membrane]ProteinO75947 (Uniprot-TrEMBL)
ATP5I [mitochondrial inner membrane]ProteinP56385 (Uniprot-TrEMBL)
ATP5J [mitochondrial inner membrane]ProteinP18859 (Uniprot-TrEMBL)
ATP5J2

[mitochondrial inner

membrane]		ProteinP56134 (Uniprot-TrEMBL)
ATP5L [mitochondrial inner membrane]ProteinO75964 (Uniprot-TrEMBL)
ATP5O [mitochondrial inner membrane]ProteinP48047 (Uniprot-TrEMBL)
ATPMetaboliteCHEBI:15422 (ChEBI)
ATPase complexComplexREACT_4862 (Reactome)
ATPase-ADP and Pi complexComplexREACT_2435 (Reactome)
ATPase-ATP complexComplexREACT_3945 (Reactome)
A_15_P101542Protein5215992 (Reactome)
COX4I1

[mitochondrial inner

membrane]		ProteinP13073 (Uniprot-TrEMBL)
COX5A [mitochondrial inner membrane]ProteinP20674 (Uniprot-TrEMBL)
COX5B [mitochondrial inner membrane]ProteinP10606 (Uniprot-TrEMBL)
COX6A1

[mitochondrial inner

membrane]		ProteinP12074 (Uniprot-TrEMBL)
COX6B1

[mitochondrial inner

membrane]		ProteinP14854 (Uniprot-TrEMBL)
COX6C(3-75)

[mitochondrial inner

membrane]		ProteinP09669 (Uniprot-TrEMBL)
COX7A2L

[mitochondrial inner

membrane]		ProteinO14548 (Uniprot-TrEMBL)
COX7B [mitochondrial inner membrane]ProteinP24311 (Uniprot-TrEMBL)
COX7C [mitochondrial inner membrane]ProteinP15954 (Uniprot-TrEMBL)
COX8A [mitochondrial inner membrane]ProteinP10176 (Uniprot-TrEMBL)
CYC1 [mitochondrial inner membrane]ProteinP08574 (Uniprot-TrEMBL)
CYCS [mitochondrial inner membrane]ProteinP99999 (Uniprot-TrEMBL)
CoQMetaboliteCHEBI:16389 (ChEBI)
Complex I -

NADH:Ubiquinone

oxidoreductase		ComplexREACT_6533 (Reactome)
CuA [mitochondrial inner membrane]MetaboliteCHEBI:28694 (ChEBI)
Cytochrome c (oxidized)ComplexREACT_13953 (Reactome)
Cytochrome c (reduced)ComplexREACT_13858 (Reactome)
Cytochrome c oxidaseComplexREACT_6661 (Reactome)
ETF (reduced)ComplexREACT_6568 (Reactome)
ETFA(1-?)

[mitochondrial

matrix]		ProteinP13804 (Uniprot-TrEMBL)
ETFB [mitochondrial matrix]ProteinP38117 (Uniprot-TrEMBL)
ETFDHProteinQ16134 (Uniprot-TrEMBL)
ETFComplexREACT_6490 (Reactome)
FA anion:UCP dimer "head-in" complexComplexREACT_6679 (Reactome)
FA anion:UCP dimer "head-out" complexComplexREACT_6437 (Reactome)
FAD [mitochondrial inner membrane]MetaboliteCHEBI:16238 (ChEBI)
FAD [mitochondrial matrix]MetaboliteCHEBI:16238 (ChEBI)
FADMetaboliteCHEBI:16238 (ChEBI)
FADH2 [mitochondrial inner membrane]MetaboliteCHEBI:17877 (ChEBI)
FADH2 [mitochondrial matrix]MetaboliteCHEBI:17877 (ChEBI)
FADH2MetaboliteCHEBI:17877 (ChEBI)
FMN [mitochondrial inner membrane]MetaboliteCHEBI:17621 (ChEBI)
Fatty Acid "head-out"CHEBI:35366 (ChEBI)
Fatty Acid "head-in"CHEBI:35366 (ChEBI)
Fatty Acid anion

"head-in" [mitochondrial inner

membrane]		MetaboliteCHEBI:28868 (ChEBI)
Fatty Acid anion "head-in"CHEBI:28868 (ChEBI)
Fatty Acid anion

"head-out" [mitochondrial inner

membrane]		MetaboliteCHEBI:28868 (ChEBI)
Fatty Acid anion "head-out"CHEBI:28868 (ChEBI)
H+MetaboliteCHEBI:15378 (ChEBI)
H2OMetaboliteCHEBI:15377 (ChEBI)
Homologues of FGA(20-866)Protein5215956 (Reactome)
Long-chain fatty acidCHEBI:15904 (ChEBI)
MT-ATP6

[mitochondrial inner

membrane]		ProteinP00846 (Uniprot-TrEMBL)
MT-ATP8

[mitochondrial inner

membrane]		ProteinP03928 (Uniprot-TrEMBL)
MT-CO1

[mitochondrial inner

membrane]		ProteinP00395 (Uniprot-TrEMBL)
MT-CO2

[mitochondrial inner

membrane]		ProteinP00403 (Uniprot-TrEMBL)
MT-CO3(1-261)

[mitochondrial inner

membrane]		ProteinP00414 (Uniprot-TrEMBL)
MT-CYB

[mitochondrial inner

membrane]		ProteinP00156 (Uniprot-TrEMBL)
MT-ND1

[mitochondrial inner

membrane]		ProteinP03886 (Uniprot-TrEMBL)
MT-ND2

[mitochondrial inner

membrane]		ProteinP03891 (Uniprot-TrEMBL)
MT-ND3

[mitochondrial inner

membrane]		ProteinP03897 (Uniprot-TrEMBL)
MT-ND4

[mitochondrial inner

membrane]		ProteinP03905 (Uniprot-TrEMBL)
MT-ND4L

[mitochondrial inner

membrane]		ProteinP03901 (Uniprot-TrEMBL)
MT-ND5

[mitochondrial inner

membrane]		ProteinP03915 (Uniprot-TrEMBL)
MT-ND6

[mitochondrial inner

membrane]		ProteinP03923 (Uniprot-TrEMBL)
NAD+MetaboliteCHEBI:15846 (ChEBI)
NADHMetaboliteCHEBI:16908 (ChEBI)
NDUFA1

[mitochondrial inner

membrane]		ProteinO15239 (Uniprot-TrEMBL)
NDUFA10

[mitochondrial inner

membrane]		ProteinO95299 (Uniprot-TrEMBL)
NDUFA11

[mitochondrial inner

membrane]		ProteinQ86Y39 (Uniprot-TrEMBL)
NDUFA12

[mitochondrial inner

membrane]		ProteinQ9UI09 (Uniprot-TrEMBL)
NDUFA13

[mitochondrial inner

membrane]		ProteinQ9P0J0 (Uniprot-TrEMBL)
NDUFA2

[mitochondrial inner

membrane]		ProteinO43678 (Uniprot-TrEMBL)
NDUFA3(1-84)

[mitochondrial inner

membrane]		ProteinO95167 (Uniprot-TrEMBL)
NDUFA4

[mitochondrial inner

membrane]		ProteinO00483 (Uniprot-TrEMBL)
NDUFA5

[mitochondrial inner

membrane]		ProteinQ16718 (Uniprot-TrEMBL)
NDUFA6

[mitochondrial inner

membrane]		ProteinP56556 (Uniprot-TrEMBL)
NDUFA7

[mitochondrial inner

membrane]		ProteinO95182 (Uniprot-TrEMBL)
NDUFA8

[mitochondrial inner

membrane]		ProteinP51970 (Uniprot-TrEMBL)
NDUFA9

[mitochondrial inner

membrane]		ProteinQ16795 (Uniprot-TrEMBL)
NDUFAB1

[mitochondrial inner

membrane]		ProteinO14561 (Uniprot-TrEMBL)
NDUFB1

[mitochondrial inner

membrane]		ProteinO75438 (Uniprot-TrEMBL)
NDUFB10(2-172)

[mitochondrial inner

membrane]		ProteinO96000 (Uniprot-TrEMBL)
NDUFB11

[mitochondrial inner

membrane]		ProteinQ9NX14 (Uniprot-TrEMBL)
NDUFB2

[mitochondrial inner

membrane]		ProteinO95178 (Uniprot-TrEMBL)
NDUFB3

[mitochondrial inner

membrane]		ProteinO43676 (Uniprot-TrEMBL)
NDUFB4

[mitochondrial inner

membrane]		ProteinO95168 (Uniprot-TrEMBL)
NDUFB5

[mitochondrial inner

membrane]		ProteinO43674 (Uniprot-TrEMBL)
NDUFB6

[mitochondrial inner

membrane]		ProteinO95139 (Uniprot-TrEMBL)
NDUFB7

[mitochondrial inner

membrane]		ProteinP17568 (Uniprot-TrEMBL)
NDUFB8

[mitochondrial inner

membrane]		ProteinO95169 (Uniprot-TrEMBL)
NDUFB9

[mitochondrial inner

membrane]		ProteinQ9Y6M9 (Uniprot-TrEMBL)
NDUFC1

[mitochondrial inner

membrane]		ProteinO43677 (Uniprot-TrEMBL)
NDUFC2

[mitochondrial inner

membrane]		ProteinO95298 (Uniprot-TrEMBL)
NDUFS1

[mitochondrial inner

membrane]		ProteinP28331 (Uniprot-TrEMBL)
NDUFS2

[mitochondrial inner

membrane]		ProteinO75306 (Uniprot-TrEMBL)
NDUFS3

[mitochondrial inner

membrane]		ProteinO75489 (Uniprot-TrEMBL)
NDUFS4

[mitochondrial inner

membrane]		ProteinO43181 (Uniprot-TrEMBL)
NDUFS5

[mitochondrial inner

membrane]		ProteinO43920 (Uniprot-TrEMBL)
NDUFS6

[mitochondrial inner

membrane]		ProteinO75380 (Uniprot-TrEMBL)
NDUFS7

[mitochondrial inner

membrane]		ProteinO75251 (Uniprot-TrEMBL)
NDUFS8

[mitochondrial inner

membrane]		ProteinO00217 (Uniprot-TrEMBL)
NDUFV1

[mitochondrial inner

membrane]		ProteinP49821 (Uniprot-TrEMBL)
NDUFV2

[mitochondrial inner

membrane]		ProteinP19404 (Uniprot-TrEMBL)
NDUFV3

[mitochondrial inner

membrane]		ProteinP56181 (Uniprot-TrEMBL)
O2MetaboliteCHEBI:15379 (ChEBI)
Pi [mitochondrial matrix]MetaboliteCHEBI:18367 (ChEBI)
PiMetaboliteCHEBI:18367 (ChEBI)
Purine nucleotideREACT_6384 (Reactome)
QH2MetaboliteCHEBI:17976 (ChEBI)
SDHA [mitochondrial inner membrane]ProteinP31040 (Uniprot-TrEMBL)
SDHB [mitochondrial inner membrane]ProteinP21912 (Uniprot-TrEMBL)
SDHC [mitochondrial inner membrane]ProteinQ99643 (Uniprot-TrEMBL)
SDHD [mitochondrial inner membrane]ProteinO14521 (Uniprot-TrEMBL)
Succinate

dehydrogenase

complex (oxidised)		ComplexREACT_3127 (Reactome)
Succinate

dehydrogenase

complex (reduced)		ComplexREACT_6402 (Reactome)
UCP dimerComplexREACT_6463 (Reactome)
UCP1(1-307)

[mitochondrial inner

membrane]		ProteinP25874 (Uniprot-TrEMBL)
UCP2 [mitochondrial inner membrane]ProteinP55851 (Uniprot-TrEMBL)
UCP3 [mitochondrial inner membrane]ProteinP55916 (Uniprot-TrEMBL)
UQCR10

[mitochondrial inner

membrane]		ProteinQ9UDW1 (Uniprot-TrEMBL)
UQCR11

[mitochondrial inner

membrane]		ProteinO14957 (Uniprot-TrEMBL)
UQCRB [mitochondrial inner membrane]ProteinP14927 (Uniprot-TrEMBL)
UQCRC1

[mitochondrial inner

membrane]		ProteinP31930 (Uniprot-TrEMBL)
UQCRC2

[mitochondrial inner

membrane]		ProteinP22695 (Uniprot-TrEMBL)
UQCRFS1(79-274)

[mitochondrial inner

membrane]		ProteinP47985 (Uniprot-TrEMBL)
UQCRH [mitochondrial inner membrane]ProteinP07919 (Uniprot-TrEMBL)
UQCRQ [mitochondrial inner membrane]ProteinO14949 (Uniprot-TrEMBL)
Ubiquinol-cytochrome c reductaseComplexREACT_6527 (Reactome)
factor X heavy chain

[extracellular

region]		Protein5216110 (Reactome)
ferriheme

[mitochondrial inner

membrane]		MetaboliteCHEBI:38574 (ChEBI)
ferroheme

[mitochondrial inner

membrane]		MetaboliteCHEBI:38573 (ChEBI)

Annotated Interactions

View all...
SourceTargetTypeDatabase referenceComment
ADPREACT_991 (Reactome)
ATPArrowREACT_1985 (Reactome)
ATPase complexArrowREACT_1985 (Reactome)
ATPase complexREACT_991 (Reactome)
ATPase-ADP and Pi complexArrowREACT_991 (Reactome)
ATPase-ADP and Pi complexREACT_190 (Reactome)
ATPase-ADP and Pi complexmim-catalysisREACT_190 (Reactome)
ATPase-ATP complexArrowREACT_190 (Reactome)
ATPase-ATP complexREACT_1985 (Reactome)
ATPase-ATP complexmim-catalysisREACT_1985 (Reactome)
CoQArrowREACT_6300 (Reactome)
CoQREACT_6169 (Reactome)
CoQREACT_6300 (Reactome)
CoQREACT_6310 (Reactome)
CoQREACT_6360 (Reactome)
Complex I -

NADH:Ubiquinone

oxidoreductase		mim-catalysisREACT_6310 (Reactome)
Cytochrome c (oxidized)ArrowREACT_6149 (Reactome)
Cytochrome c (oxidized)REACT_6300 (Reactome)
Cytochrome c (reduced)ArrowREACT_6300 (Reactome)
Cytochrome c (reduced)REACT_6149 (Reactome)
Cytochrome c oxidasemim-catalysisREACT_6149 (Reactome)
ETF (reduced)ArrowREACT_6154 (Reactome)
ETF (reduced)REACT_6169 (Reactome)
ETFArrowREACT_6169 (Reactome)
ETFDHmim-catalysisREACT_6169 (Reactome)
ETFREACT_6154 (Reactome)
ETFmim-catalysisREACT_6154 (Reactome)
FA anion:UCP dimer "head-in" complexArrowREACT_6165 (Reactome)
FA anion:UCP dimer "head-in" complexREACT_6188 (Reactome)
FA anion:UCP dimer "head-in" complexmim-catalysisREACT_6188 (Reactome)
FA anion:UCP dimer "head-out" complexArrowREACT_6188 (Reactome)
FA anion:UCP dimer "head-out" complexREACT_6218 (Reactome)
FADArrowREACT_6154 (Reactome)
FADH2REACT_6154 (Reactome)
Fatty Acid "head-out"ArrowREACT_6205 (Reactome)
Fatty Acid "head-out"REACT_6151 (Reactome)
Fatty Acid "head-in"ArrowREACT_6151 (Reactome)
Fatty Acid "head-in"REACT_6302 (Reactome)
Fatty Acid anion "head-in"ArrowREACT_6302 (Reactome)
Fatty Acid anion "head-in"REACT_6165 (Reactome)
Fatty Acid anion "head-out"ArrowREACT_6218 (Reactome)
Fatty Acid anion "head-out"REACT_6205 (Reactome)
H+ArrowREACT_1985 (Reactome)
H+ArrowREACT_6149 (Reactome)
H+ArrowREACT_6300 (Reactome)
H+ArrowREACT_6302 (Reactome)
H+ArrowREACT_6310 (Reactome)
H+ArrowREACT_6312 (Reactome)
H+REACT_1985 (Reactome)
H+REACT_6149 (Reactome)
H+REACT_6205 (Reactome)
H+REACT_6300 (Reactome)
H+REACT_6310 (Reactome)
H+REACT_6312 (Reactome)
H2OArrowREACT_190 (Reactome)
H2OArrowREACT_6149 (Reactome)
Long-chain fatty acidArrowREACT_6312 (Reactome)
NAD+ArrowREACT_6310 (Reactome)
NADHREACT_6310 (Reactome)
O2REACT_6149 (Reactome)
PiREACT_991 (Reactome)
Purine nucleotideTBarREACT_6312 (Reactome)
QH2ArrowREACT_6169 (Reactome)
QH2ArrowREACT_6300 (Reactome)
QH2ArrowREACT_6310 (Reactome)
QH2ArrowREACT_6360 (Reactome)
QH2REACT_6300 (Reactome)
REACT_190 (Reactome) In the tight configuration, the beta subunit catalyzes the reaction of ADP + Pi to ATP + water. ATP is still tightly bound to the subunit at this stage.
REACT_1985 (Reactome) In the last step, the beta subunit is converted to the open form and ATP is released. Passage of protons through the Fo part causes a ring of approximately 10 subunits to rotate. This rotation in turn drives the rotation of the gamma subunits, which forms part of one of the stalks. The gamma subunit moves between the three beta subunits which are held in place by the second stalk which can be regarded as a stator. The polypeptide called OSCP connects the stator stalk to the assembly of alpha and beta subunits. It is this step that is coupled to proton translocation as energy is required to break the strong bond between ATP and the protein.


REACT_6149 (Reactome) Complex IV (cytochrome oxidase) contains the hemeprotein cytochrome a and a3. It also contains copper atoms which undergo a transition from Cu+ to Cu2+ during the transfer of electrons through the complex to molecular oxygen. A bimetallic centre containing a copper atom and a heme-linked iron protein binds oxygen after 4 electrons have been picked up. Water, the final product of oxygen reduction, is then released. Oxygen is the final electron acceptor in the respiratory chain. The overall reaction can be summed as below:
4Cyt c(red.) + 12H+in + O2 -> 4Cyt c(ox.) + 2H2O + 8H+out

Four protons are taken up from the matrix side of the membrane to form the water (scalar protons). Wikstrom (1977) suggests 4 protons are additionally transferred out from the matrix to the intermembrane space.
REACT_6151 (Reactome) At the beginning of this reaction, 1 molecule of 'Fatty Acid "head-out"' is present. At the end of this reaction, 1 molecule of 'Fatty Acid "head-in"' is present.

This reaction takes place in the 'mitochondrial inner membrane'.

REACT_6154 (Reactome) Electron transfer flavoprotein, ETF, a 63kDa heterodimer composed of alpha and beta subunit, binds one FAD and one AMP per dimer. ETF resides on the matrix face of the mitochondrial inner membrane. Reducing equivalents from the beta-oxidation of fatty acyl CoAs are transferred to ETF, reducing the ETF-bound FAD to FADH2.
REACT_6165 (Reactome) A FA anion diffuses laterally within the membrane towards UCP. The membrane potential drives the FA anion to an energy well halfway up on UCP. The electric field created by the redox-linked proton ejection drives the head group to the energy well.
REACT_6169 (Reactome) ETF-ubiquinone oxidoreductase (ETF-QO), catalyzes the re-oxidation of reduced ETF, with ubiquinone as the electron acceptor.
REACT_6188 (Reactome) The FA anion which was facing the matrix side of the inner mitochondrial membrane now flip-flops over to the intermembrane space-side of the membrane.
REACT_6205 (Reactome) At the beginning of this reaction, 1 molecule of 'H+', and 1 molecule of 'Fatty Acid anion "head-out"' are present. At the end of this reaction, 1 molecule of 'Fatty Acid "head-out"' is present.

This reaction takes place in the 'mitochondrial inner membrane'.

REACT_6218 (Reactome) At the beginning of this reaction, 1 molecule of 'FA anion:UCP dimer "head-out" complex' is present. At the end of this reaction, 1 molecule of 'UCP dimer', and 1 molecule of 'Fatty Acid anion "head-out"' are present.

This reaction takes place in the 'mitochondrial inner membrane'.

REACT_6300 (Reactome) The Protonmotive Q cycle is the mechanism by which complex III transfers electrons from ubiquinol to cytochrome c, linking this process to translocation of protons across the membrane. This cycle is complicated by the fact that both ubiquinol is oxidised and ubiquinone is reduced during this process. Through a complex series of electron transfers, Complex III consumes two molecules of ubiquinol (QH2) and two molecules of oxidized cytochrome c, generates one molecule of ubiquinone (Q) and two molecules of reduced cytochrome c, regenerates one molecule of ubiquinol (QH2), and mediates the translocation of two protons from the mitochondrial matrix to the mitochondrial intermembrane space.

The overall reaction can be summed up as below:
2QH2 + 2cyt c(ox.) + Q + 2H+matrix -> 2Q + 2cyt c(red.) + QH2 + 4H+memb. space



REACT_6302 (Reactome) At the beginning of this reaction, 1 molecule of 'Fatty Acid "head-in"' is present. At the end of this reaction, 1 molecule of 'H+', and 1 molecule of 'Fatty Acid anion "head-in"' are present.

This reaction takes place in the 'mitochondrial inner membrane'.

REACT_6310 (Reactome) Complex I (NADH:ubiquinone oxidoreductase or NADH dehydrogenase) utilizes NADH formed from glycolysis and the TCA cycle to pump protons out of the mitochondrial matrix. It is the largest enzyme complex in the electron transport chain, containing 45 subunits. Seven subunits (ND1-6, ND4L) are encoded by mitochondrial DNA (Loeffen et al [1998]), the remainder are encoded in the nucleus. The enzyme has a FMN prosthetic group and 8 Iron-Sulfur (Fe-S) clusters. The electrons from NADH oxidation pass through the flavin (FMN) and Fe-S clusters to ubiquinone (CoQ). This electron transfer is coupled with the translocation of protons from the mitochondrial matrix to the intermembrane space. For each electron transferred, 2 protons can be pumped out of the matrix. As there are 2 electrons transferred, 4 protons can be pumped out.
Complex I is made up of 3 sub-complexes - Iron-Sulfur protein fraction (IP), Flavoprotein fraction (FP) and the Hydrophobic protein fraction (HP), probably arranged in an L-shaped structure with the IP and FP fractions protruding into the mitochondrial matrix and the HP arm lying within the inner mitochondrial membrane. The overall reaction can be summed as below:
NADH + Ubiquinone + 5H+matrix -> NAD+ + Ubiquinol + 4H+memb. space

The electrons from complex I are transferred to ubiquinone (Coenzyme Q, CoQ), a small mobile carrier of electrons located within the inner membrane. Ubiquinone is reduced to ubiquinol during this process.
REACT_6312 (Reactome) In this reaction, 1 molecule of 'H+' is translocated from mitochondrial intermembrane space to mitochondrial matrix.

This reaction takes place in the 'mitochondrial inner membrane' and is mediated by the 'hydrogen ion transporter activity' of 'UCP dimer'.
REACT_6360 (Reactome) This event is deduced on the basis of bovine experimental data.
Complex II (succinate dehydrogenase) transfers electrons from the TCA cycle to ubiquinone. The 6th step in the TCA cycle is where succinate is dehydrogenated to fumarate with subsequent reduction of FAD to FADH2. FADH2 provides the electrons for the transport chain. Succinate dehydrogenase belongs to subclass 1 of the SQR family (succinate:quinone reductase) (classified by Hagerhall, C and Hederstedt, L [1996]).
It consists of 4 subunits (referred to as A, B, C and D), all nuclear-encoded and is located on the matrix side of the inner mitochondrial membrane. Subunits A and B are hydrophilic whereas subunits C and D are integral proteins of the inner membrane. SQRs usually contain 3 Fe-S clusters bound by the B subunit. Succinate dehydrogenase contains one [2Fe-2S] cluster, one [4Fe-4S] cluster and one [3Fe-4S] cluster. Additionally, the A subunit has a covalently-bound FAD group. Reduced complex II has this FAD converted to FADH2. The electrons from complex II are transferred to ubiquinone (also called Q, Coenzyme Q or CoQ), a small mobile carrier of electrons located within the inner membrane. Ubiquinone is reduced to ubiquinol during this process.
REACT_991 (Reactome) The beta subunit has 3 conformations; tight, open and loose. ADP and Pi bind to the subunit in the loose form. On binding, this subunit is converted to the tight configuration.
Succinate

dehydrogenase

complex (oxidised)		ArrowREACT_6360 (Reactome)
Succinate

dehydrogenase

complex (reduced)		REACT_6360 (Reactome)
Succinate

dehydrogenase

complex (reduced)		mim-catalysisREACT_6360 (Reactome)
UCP dimerArrowREACT_6218 (Reactome)
UCP dimerREACT_6165 (Reactome)
UCP dimermim-catalysisREACT_6312 (Reactome)
Ubiquinol-cytochrome c reductasemim-catalysisREACT_6300 (Reactome)
Retrieved from "https://classic.wikipathways.org/index.php/Pathway:WP1902"