KEGG   PATHWAY: ace00020Help
ace00020                    Pathway                                

Citrate cycle (TCA cycle) - Acidothermus cellulolyticus
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
ace00020  Citrate cycle (TCA cycle)

Ortholog table
ace_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:ace00020]
ace_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:ace00020]
Other DBs
GO: 0006099
Acidothermus cellulolyticus [GN:ace]
Acel_0115  citrate synthase [KO:K01647] [EC:]
Acel_1394  aconitase [KO:K01681] [EC:]
Acel_0388  isocitrate dehydrogenase (NADP) [KO:K00031] [EC:]
Acel_0586  2-oxoglutarate dehydrogenase E1 component [KO:K00164] [EC:]
Acel_0935  2-oxoglutarate dehydrogenase E2 component [KO:K00658] [EC:]
Acel_0936  dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
Acel_0284  pyruvate flavodoxin/ferredoxin oxidoreductase domain protein [KO:K00174] [EC:]
Acel_0283  thiamine pyrophosphate enzyme domain protein TPP-binding protein [KO:K00175] [EC:]
Acel_0381  succinyl-CoA synthetase (ADP-forming) alpha subunit [KO:K01902] [EC:]
Acel_0380  succinyl-CoA synthetase (ADP-forming) beta subunit [KO:K01903] [EC:]
Acel_1865  succinate dehydrogenase subunit A [KO:K00239] [EC:]
Acel_1864  succinate dehydrogenase subunit B [KO:K00240] [EC:]
Acel_1879  fumarase [KO:K01679] [EC:]
Acel_0387  malate dehydrogenase (NAD) [KO:K00024] [EC:]
Acel_1046  Pyruvate dehydrogenase (acetyl-transferring) [KO:K00161] [EC:]
Acel_0033  Pyruvate dehydrogenase (acetyl-transferring) [KO:K00161] [EC:]
Acel_0590  Pyruvate dehydrogenase (acetyl-transferring) [KO:K00161] [EC:]
Acel_0589  Transketolase, central region [KO:K00162] [EC:]
Acel_0032  Transketolase, central region [KO:K00162] [EC:]
Acel_0588  catalytic domain of components of various dehydrogenase complexes [KO:K00627] [EC:]
Acel_0031  catalytic domain of components of various dehydrogenase complexes [KO:K00627] [EC:]
Acel_0701  pyruvate ferredoxin oxidoreductase, alpha subunit [KO:K00169] [EC:]
Acel_0702  pyruvate ferredoxin oxidoreductase, beta subunit [KO:K00170] [EC:]
Acel_0700  pyruvate/ketoisovalerate oxidoreductase, gamma subunit [KO:K00172] [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)
ace00010  Glycolysis / Gluconeogenesis
ace00053  Ascorbate and aldarate metabolism
ace00061  Fatty acid biosynthesis
ace00071  Fatty acid degradation
ace00220  Arginine biosynthesis
ace00250  Alanine, aspartate and glutamate metabolism
ace00280  Valine, leucine and isoleucine degradation
ace00350  Tyrosine metabolism
ace00471  D-Glutamine and D-glutamate metabolism
ace00630  Glyoxylate and dicarboxylate metabolism
KO pathway

DBGET integrated database retrieval system