KEGG   PATHWAY: rpc00020Help
rpc00020                    Pathway                                

Citrate cycle (TCA cycle) - Rhodopseudomonas palustris BisB18
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
rpc00020  Citrate cycle (TCA cycle)

Ortholog table
rpc_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:rpc00020]
rpc_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:rpc00020]
rpc_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:rpc00020]
rpc_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:rpc00020]
rpc_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:rpc00020]
Other DBs
BSID: 32595
GO: 0006099
Rhodopseudomonas palustris BisB18 [GN:rpc]
RPC_2450  citrate synthase [KO:K01647] [EC:]
RPC_0204  aconitase [KO:K01681] [EC:]
RPC_1576  isocitrate dehydrogenase (NADP) [KO:K00031] [EC:]
RPC_0191  2-oxoglutarate dehydrogenase E1 component [KO:K00164] [EC:]
RPC_0190  2-oxoglutarate dehydrogenase E2 component [KO:K00658] [EC:]
RPC_2493  dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
RPC_0183  dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
RPC_0695  2-oxoglutarate ferredoxin oxidoreductase, alpha subunit [KO:K00174] [EC:]
RPC_0696  2-oxoglutarate ferredoxin oxidoreductase, beta subunit [KO:K00175] [EC:]
RPC_0697  pyruvate ferredoxin/flavodoxin oxidoreductase [KO:K00177] [EC:]
RPC_0192  succinyl-CoA synthetase (ADP-forming) alpha subunit [KO:K01902] [EC:]
RPC_0193  succinyl-CoA synthetase (ADP-forming) beta subunit [KO:K01903] [EC:]
RPC_0254  Acetyl-CoA hydrolase [KO:K18118] [EC:]
RPC_0070  succinate dehydrogenase subunit A [KO:K00239] [EC:]
RPC_0068  succinate dehydrogenase subunit B [KO:K00240] [EC:]
RPC_0072  succinate dehydrogenase subunit C [KO:K00241]
RPC_0071  succinate dehydrogenase subunit D [KO:K00242]
RPC_1533  fumarase [KO:K01676] [EC:]
RPC_3271  fumarase [KO:K01679] [EC:]
RPC_4584  malate dehydrogenase (NAD) [KO:K00024] [EC:]
RPC_0194  malate dehydrogenase (NAD) [KO:K00024] [EC:]
RPC_0599  Phosphoenolpyruvate carboxykinase (ATP) [KO:K01610] [EC:]
RPC_2489  Pyruvate dehydrogenase (lipoamide) [KO:K00161] [EC:]
RPC_2490  Transketolase, central region [KO:K00162] [EC:]
RPC_2492  Dihydrolipoamide acetyltransferase, long form [KO:K00627] [EC:]
RPC_0704  pyruvate flavodoxin/ferredoxin oxidoreductase-like [KO:K03737] [EC:1.2.7.-]
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
LinkDB All DBs

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