KEGG   PATHWAY: abn00020Help
abn00020                    Pathway                                

Citrate cycle (TCA cycle) - Acinetobacter baumannii AB0057
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
abn00020  Citrate cycle (TCA cycle)

Ortholog table
abn_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:abn00020]
abn_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:abn00020]
abn_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:abn00020]
abn_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:abn00020]
abn_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:abn00020]
Other DBs
GO: 0006099
Acinetobacter baumannii AB0057 [GN:abn]
AB57_06550  gltA; GltA [KO:K01647] [EC:]
AB57_0636  aconitate hydratase 1 [KO:K01681] [EC:]
AB57_2462  bifunctional aconitate hydratase 2/2-methylisocitrate dehydratase [KO:K01682] [EC:]
AB57_2919  NADP-dependent isocitrate dehydrogenase [KO:K00031] [EC:]
AB57_2921  isocitrate dehydrogenase (NADP(+)) [KO:K00031] [EC:]
AB57_3126  2-oxoglutarate dehydrogenase E1 component [KO:K00164] [EC:]
AB57_3125  dihydrolipoamide succinyltransferase [KO:K00658] [EC:]
AB57_3124  dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
AB57_3436  dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
AB57_1931  dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
AB57_3122  succinate--CoA ligase subunit alpha [KO:K01902] [EC:]
AB57_3123  succinate--CoA ligase subunit beta [KO:K01903] [EC:]
AB57_3679  propionyl-CoA--succinate CoA transferase [KO:K18118] [EC:]
AB57_3129  succinate dehydrogenase flavoprotein subunit [KO:K00239] [EC:]
AB57_3128  sdhB; succinate dehydrogenase iron-sulfur subunit [KO:K00240] [EC:]
AB57_3131  succinate dehydrogenase, cytochrome b556 subunit [KO:K00241]
AB57_3130  succinate dehydrogenase, hydrophobic membrane anchor protein [KO:K00242]
AB57_0584  fumarate hydratase [KO:K01676] [EC:]
AB57_2334  fumarate hydratase, class II [KO:K01679] [EC:]
AB57_3474  malate dehydrogenase [KO:K00024] [EC:]
AB57_1001  malate dehydrogenase (acceptor) [KO:K00116] [EC:]
AB57_3085  phosphoenolpyruvate carboxykinase [KO:K01596] [EC:]
AB57_3777  pyruvate dehydrogenase (acetyl-transferring), homodimeric type [KO:K00163] [EC:]
AB57_1930  diaminohydroxyphosphoribosylaminopyrimidine deaminase [KO:K00627] [EC:]
AB57_3776  pyruvate dehydrogenase complex dihydrolipoyllysine-residue acetyltransferase [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)
abn00010  Glycolysis / Gluconeogenesis
abn00053  Ascorbate and aldarate metabolism
abn00061  Fatty acid biosynthesis
abn00071  Fatty acid degradation
abn00220  Arginine biosynthesis
abn00250  Alanine, aspartate and glutamate metabolism
abn00280  Valine, leucine and isoleucine degradation
abn00350  Tyrosine metabolism
abn00471  D-Glutamine and D-glutamate metabolism
abn00630  Glyoxylate and dicarboxylate metabolism
KO pathway

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