KEGG   PATHWAY: bsu00020
bsu00020                    Pathway                                

Citrate cycle (TCA cycle) - Bacillus subtilis subsp. subtilis 168
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
Pathway map
bsu00020  Citrate cycle (TCA cycle)

bsu_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:bsu00020]
bsu_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:bsu00020]
bsu_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:bsu00020]
bsu_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:bsu00020]
bsu_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:bsu00020]
Other DBs
GO: 0006099
Bacillus subtilis subsp. subtilis 168 [GN:bsu]
BSU09440  citA; citrate synthase [KO:K01647] [EC:]
BSU29140  citZ; citrate synthase 2 [KO:K01647] [EC:]
BSU24140  mmgD; 2-methylcitrate synthase [KO:K01647] [EC:]
BSU18000  citB; aconitate hydratase [KO:K01681] [EC:]
BSU29130  icd; isocitrate dehydrogenase [KO:K00031] [EC:]
BSU19370  sucA; 2-oxoglutarate dehydrogenase subunit E1 [KO:K00164] [EC:]
BSU19360  odhB; dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex [KO:K00658] [EC:]
BSU14610  pdhD; dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
BSU24060  lpdV; dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
BSU08090  acoL; dihydrolipoyl dehydrogenase [KO:K00382] [EC:]
BSU16100  sucD; succinyl-CoA ligase [ADP-forming] subunit alpha [KO:K01902] [EC:]
BSU16090  sucC; succinyl-CoA ligase [ADP-forming] subunit beta [KO:K01903] [EC:]
BSU28440  sdhA; succinate dehydrogenase flavoprotein subunit [KO:K00239] [EC:]
BSU28430  sdhB; succinate dehydrogenase iron-sulfur subunit [KO:K00240] [EC:]
BSU28450  sdhC; succinate dehydrogenase cytochrome b558 subunit [KO:K00241]
BSU33040  fumC; fumarate hydratase class II [KO:K01679] [EC:]
BSU29120  mdh; malate dehydrogenase [KO:K00024] [EC:]
BSU14860  pycA; pyruvate carboxylase [KO:K01958] [EC:]
BSU30560  pckA; phosphoenolpyruvate carboxykinase [KO:K01610] [EC:]
BSU14580  pdhA; pyruvate dehydrogenase E1 component subunit alpha [KO:K00161] [EC:]
BSU14590  pdhB; pyruvate dehydrogenase E1 component subunit beta [KO:K00162] [EC:]
BSU08080  acoC; dihydrolipoyllysine-residue acetyltransferase component of acetoin cleaving system [KO:K00627] [EC:]
BSU14600  pdhC; dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex [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)
bsu00010  Glycolysis / Gluconeogenesis
bsu00053  Ascorbate and aldarate metabolism
bsu00061  Fatty acid biosynthesis
bsu00071  Fatty acid degradation
bsu00190  Oxidative phosphorylation
bsu00220  Arginine biosynthesis
bsu00250  Alanine, aspartate and glutamate metabolism
bsu00280  Valine, leucine and isoleucine degradation
bsu00350  Tyrosine metabolism
bsu00470  D-Amino acid metabolism
bsu00630  Glyoxylate and dicarboxylate metabolism
KO pathway

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