KEGG   PATHWAY: gwc00020Help
gwc00020                    Pathway                                

Citrate cycle (TCA cycle) - Geobacillus sp. WCH70
The citrate cycle (TCA cycle, Krebs cycle) is an important aerobic pathway for the final steps of the oxidation of carbohydrates and fatty acids. The cycle starts with acetyl-CoA, the activated form of acetate, derived from glycolysis and pyruvate oxidation for carbohydrates and from beta oxidation of fatty acids. The two-carbon acetyl group in acetyl-CoA is transferred to the four-carbon compound of oxaloacetate to form the six-carbon compound of citrate. In a series of reactions two carbons in citrate are oxidized to CO2 and the reaction pathway supplies NADH for use in the oxidative phosphorylation and other metabolic processes. The pathway also supplies important precursor metabolites including 2-oxoglutarate. At the end of the cycle the remaining four-carbon part is transformed back to oxaloacetate. According to the genome sequence data, many organisms seem to lack genes for the full cycle [MD:M00009], but contain genes for specific segments [MD:M00010 M00011].
Metabolism; Carbohydrate metabolism
BRITE hierarchy
Pathway map
gwc00020  Citrate cycle (TCA cycle)

Ortholog table
gwc_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:gwc00020]
gwc_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:gwc00020]
gwc_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:gwc00020]
gwc_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:gwc00020]
gwc_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:gwc00020]
Other DBs
BSID: 99935
GO: 0006099
Geobacillus sp. WCH70 [GN:gwc]
GWCH70_2679  2-methylcitrate synthase/citrate synthase II [KO:K01647] [EC:]
GWCH70_1258  aconitate hydratase 1 [KO:K01681] [EC:]
GWCH70_0444  isocitrate dehydrogenase [KO:K00031] [EC:]
GWCH70_2678  isocitrate dehydrogenase, NADP-dependent [KO:K00031] [EC:]
GWCH70_0919  2-oxoglutarate dehydrogenase, E1 subunit [KO:K00164] [EC:]
GWCH70_0920  2-oxoglutarate dehydrogenase, E2 subunit, dihydrolipoamide succinyltransferase [KO:K00658] [EC:]
GWCH70_2306  dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
GWCH70_0955  dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
GWCH70_1195  pyruvate flavodoxin/ferredoxin oxidoreductase domain protein [KO:K00174] [EC:]
GWCH70_1196  pyruvate ferredoxin/flavodoxin oxidoreductase, beta subunit [KO:K00175] [EC:]
GWCH70_1100  succinyl-CoA synthetase, alpha subunit [KO:K01902] [EC:]
GWCH70_1099  succinyl-CoA synthetase, beta subunit [KO:K01903] [EC:]
GWCH70_0438  succinate CoA transferase [KO:K18118] [EC:]
GWCH70_2606  succinate dehydrogenase or fumarate reductase, flavoprotein subunit [KO:K00239] [EC:]
GWCH70_2605  succinate dehydrogenase and fumarate reductase iron-sulfur protein [KO:K00240] [EC:]
GWCH70_2607  succinate dehydrogenase (or fumarate reductase) cytochrome b subunit, b558 family [KO:K00241]
GWCH70_0425  hydro-lyase, Fe-S type, tartrate/fumarate subfamily, alpha subunit [KO:K01676] [EC:]
GWCH70_2677  malate dehydrogenase, NAD-dependent [KO:K00024] [EC:]
GWCH70_1433  malate/quinone oxidoreductase [KO:K00116] [EC:]
GWCH70_0980  pyruvate carboxylase [KO:K01958] [EC:]
GWCH70_2779  phosphoenolpyruvate carboxykinase (ATP) [KO:K01610] [EC:]
GWCH70_3161  pyruvate dehydrogenase (acetyl-transferring) E1 component, alpha subunit [KO:K00161] [EC:]
GWCH70_0952  pyruvate dehydrogenase (acetyl-transferring) E1 component, alpha subunit [KO:K00161] [EC:]
GWCH70_3160  Transketolase central region [KO:K00162] [EC:]
GWCH70_0953  Transketolase central region [KO:K00162] [EC:]
GWCH70_3162  catalytic domain of components of various dehydrogenase complexes [KO:K00627] [EC:]
GWCH70_0954  Dihydrolipoyllysine-residue (2-methylpropanoyl)transferase [KO:K00627] [EC:]
C00022  Pyruvate
C00024  Acetyl-CoA
C00026  2-Oxoglutarate
C00036  Oxaloacetate
C00042  Succinate
C00068  Thiamin diphosphate
C00074  Phosphoenolpyruvate
C00091  Succinyl-CoA
C00122  Fumarate
C00149  (S)-Malate
C00158  Citrate
C00311  Isocitrate
C00417  cis-Aconitate
C05125  2-(alpha-Hydroxyethyl)thiamine diphosphate
C05379  Oxalosuccinate
C05381  3-Carboxy-1-hydroxypropyl-ThPP
C15972  Enzyme N6-(lipoyl)lysine
C15973  Enzyme N6-(dihydrolipoyl)lysine
C16254  [Dihydrolipoyllysine-residue succinyltransferase] S-succinyldihydrolipoyllysine
C16255  [Dihydrolipoyllysine-residue acetyltransferase] S-acetyldihydrolipoyllysine
(map 2)
Nishizuka Y (ed).
[Metabolic Maps] (In Japanese)
Tokyo Kagaku Dojin (1980)
(map 3)
Nishizuka Y, Seyama Y, Ikai A, Ishimura Y, Kawaguchi A (eds).
[Cellular Functions and Metabolic Maps] (In Japanese)
Tokyo Kagaku Dojin (1997)
Michal G.
Biochemical Pathways
Wiley (1999)
KO pathway

DBGET integrated database retrieval system