KEGG   PATHWAY: labr00020
Entry
labr00020                   Pathway                                
Name
Citrate cycle (TCA cycle) - Labrenzia sp. VG12
Description
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].
Class
Metabolism; Carbohydrate metabolism
Pathway map
labr00020  Citrate cycle (TCA cycle)
labr00020

Module
labr_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:labr00020]
labr_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:labr00020]
labr_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:labr00020]
labr_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:labr00020]
labr_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:labr00020]
Other DBs
GO: 0006099
Organism
Labrenzia sp. VG12 [GN:labr]
Gene
CHH27_06725  gltA; citrate (Si)-synthase [KO:K01647] [EC:2.3.3.1]
CHH27_20085  citrate synthase [KO:K01647] [EC:2.3.3.1]
CHH27_20090  citrate synthase/methylcitrate synthase [KO:K01647] [EC:2.3.3.1]
CHH27_18220  acnA; aconitate hydratase 1 [KO:K27802] [EC:4.2.1.3 4.2.1.99]
CHH27_13340  bifunctional aconitate hydratase 2/2-methylisocitrate dehydratase [KO:K01682] [EC:4.2.1.3 4.2.1.99]
CHH27_09570  isocitrate dehydrogenase (NADP(+)) [KO:K00031] [EC:1.1.1.42]
CHH27_09605  isocitrate dehydrogenase (NADP(+)) [KO:K00031] [EC:1.1.1.42]
CHH27_21930  2-oxoglutarate dehydrogenase E1 component [KO:K00164] [EC:1.2.4.2]
CHH27_21935  dihydrolipoyllysine-residue succinyltransferase [KO:K00658] [EC:2.3.1.61]
CHH27_06230  lpdA; dihydrolipoyl dehydrogenase [KO:K00382] [EC:1.8.1.4]
CHH27_16140  lpdA; dihydrolipoyl dehydrogenase [KO:K00382] [EC:1.8.1.4]
CHH27_21955  dihydrolipoyl dehydrogenase [KO:K00382] [EC:1.8.1.4]
CHH27_22925  ferredoxin oxidoreductase [KO:K00174] [EC:1.2.7.3 1.2.7.11]
CHH27_22920  2-oxoglutarate ferredoxin oxidoreductase subunit beta [KO:K00175] [EC:1.2.7.3 1.2.7.11]
CHH27_21925  succinate--CoA ligase subunit alpha [KO:K01902] [EC:6.2.1.5]
CHH27_21915  succinate--CoA ligase subunit beta [KO:K01903] [EC:6.2.1.5]
CHH27_21795  succinate dehydrogenase flavoprotein subunit [KO:K00239] [EC:1.3.5.1]
CHH27_21805  succinate dehydrogenase iron-sulfur subunit [KO:K00240] [EC:1.3.5.1]
CHH27_21785  sdhC; succinate dehydrogenase, cytochrome b556 subunit [KO:K00241]
CHH27_21790  sdhD; succinate dehydrogenase, hydrophobic membrane anchor protein [KO:K00242]
CHH27_04090  fumarate hydratase [KO:K01676] [EC:4.2.1.2]
CHH27_06690  fumC; fumarate hydratase, class II [KO:K01679] [EC:4.2.1.2]
CHH27_21910  mdh; malate dehydrogenase [KO:K00024] [EC:1.1.1.37]
CHH27_22090  phosphoenolpyruvate carboxykinase (ATP) [KO:K01610] [EC:4.1.1.49]
CHH27_06245  pdhA; pyruvate dehydrogenase (acetyl-transferring) E1 component subunit alpha [KO:K00161] [EC:1.2.4.1]
CHH27_06240  pyruvate dehydrogenase complex E1 component subunit beta [KO:K00162] [EC:1.2.4.1]
CHH27_06235  pyruvate dehydrogenase complex dihydrolipoamide acetyltransferase [KO:K00627] [EC:2.3.1.12]
CHH27_05000  porA; pyruvate ferredoxin oxidoreductase [KO:K00169] [EC:1.2.7.1]
CHH27_05005  pyruvate ferredoxin oxidoreductase [KO:K00170] [EC:1.2.7.1]
CHH27_04995  2-oxoacid:acceptor oxidoreductase [KO:K00172] [EC:1.2.7.1]
Compound
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
Reference
  Authors
Nishizuka Y (ed).
  Title
[Metabolic Maps] (In Japanese)
  Journal
Tokyo Kagaku Dojin (1980)
Reference
  Authors
Nishizuka Y, Seyama Y, Ikai A, Ishimura Y, Kawaguchi A (eds).
  Title
[Cellular Functions and Metabolic Maps] (In Japanese)
  Journal
Tokyo Kagaku Dojin (1997)
Reference
  Authors
Michal G.
  Title
Biochemical Pathways
  Journal
Wiley (1999)
Related
pathway
labr00010  Glycolysis / Gluconeogenesis
labr00053  Ascorbate and aldarate metabolism
labr00061  Fatty acid biosynthesis
labr00071  Fatty acid degradation
labr00190  Oxidative phosphorylation
labr00220  Arginine biosynthesis
labr00250  Alanine, aspartate and glutamate metabolism
labr00280  Valine, leucine and isoleucine degradation
labr00350  Tyrosine metabolism
labr00470  D-Amino acid metabolism
labr00630  Glyoxylate and dicarboxylate metabolism
KO pathway
ko00020   
LinkDB

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