KEGG   PATHWAY: ebe00020
Entry
ebe00020                    Pathway                                
Name
Citrate cycle (TCA cycle) - Escherichia coli BL21(DE3)
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
ebe00020  Citrate cycle (TCA cycle)
ebe00020

Module
ebe_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:ebe00020]
ebe_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:ebe00020]
ebe_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:ebe00020]
ebe_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:ebe00020]
ebe_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:ebe00020]
Other DBs
GO: 0006099
Organism
Escherichia coli BL21(DE3) [GN:ebe]
Gene
B21_00669  gltA; citrate synthase monomer, subunit of citrate synthase [KO:K01647] [EC:2.3.3.1]
B21_01264  acnA; aconitate hydratase 1 [KO:K01681] [EC:4.2.1.3]
B21_00116  acnB; bifunctional aconitate hydratase 2 and 2-methylisocitrate dehydratase [KO:K01682] [EC:4.2.1.3 4.2.1.99]
B21_01142  icd; isocitrate dehydrogenase [KO:K00031] [EC:1.1.1.42]
B21_00674  sucA; E1(0) component of 2-oxoglutarate dehydrogenase, subunit of 2-oxoglutarate decarboxylase, thiamin-requiring and 2-oxoglutarate dehydrogenase complex [KO:K00164] [EC:1.2.4.2]
B21_00675  sucB; sucB, subunit of dihydrolipoyltranssuccinylase and 2-oxoglutarate dehydrogenase complex [KO:K00658] [EC:2.3.1.61]
B21_00114  lpd; E3 monomer, subunit of lipoamide dehydrogenase, pyruvate dehydrogenase multienzyme complex, glycine cleavage system and 2-oxoglutarate dehydrogenase complex [KO:K00382] [EC:1.8.1.4]
B21_00677  sucD; succinyl-CoA synthetase, alpha subunit, subunit of succinyl-CoA synthetase [KO:K01902] [EC:6.2.1.5]
B21_00676  sucC; succinyl-CoA synthetase, beta subunit, subunit of succinyl-CoA synthetase [KO:K01903] [EC:6.2.1.5]
B21_00672  sdhA; succinate dehydrogenase flavoprotein, subunit of succinate dehydrogenase [KO:K00239] [EC:1.3.5.1]
B21_00673  sdhB; succinate dehydrogenase iron-sulfur protein, subunit of succinate dehydrogenase [KO:K00240] [EC:1.3.5.1]
B21_00670  sdhC; succinate dehydrogenase membrane protein, subunit of succinate dehydrogenase [KO:K00241]
B21_00671  sdhD; succinate dehydrogenase membrane protein, subunit of succinate dehydrogenase [KO:K00242]
B21_03988  frdA; fumarate reductase flavoprotein, subunit of fumarate reductase [KO:K00244] [EC:1.3.5.1]
B21_03987  frdB; fumarate reductase iron-sulfur protein, subunit of fumarate reductase [KO:K00245] [EC:1.3.5.1]
B21_03986  frdC; fumarate reductase membrane protein, subunit of fumarate reductase [KO:K00246]
B21_03985  frdD; fumarate reductase membrane protein, subunit of fumarate reductase [KO:K00247]
B21_01571  fumA; fumarase A monomer, subunit of fumarase A [KO:K01676] [EC:4.2.1.2]
B21_03954  fumB; fumarase B monomer, subunit of fumarase B [KO:K01676] [EC:4.2.1.2]
B21_01570  fumC; fumarase C monomer, subunit of fumarase C [KO:K01679] [EC:4.2.1.2]
B21_01634  ydhZ; predicted protein [KO:K01675] [EC:4.2.1.2]
B21_02723  yggD; predicted DNA-binding transcriptional regulator [KO:K01774] [EC:4.2.1.2]
B21_03047  mdh; malate dehydrogenase [KO:K00024] [EC:1.1.1.37]
B21_02096  mqo; malate:quinone oxidoreductase [KO:K00116] [EC:1.1.5.4]
B21_03207  pck; phosphoenolpyruvate carboxykinase (ATP) [KO:K01610] [EC:4.1.1.49]
B21_00112  aceE; E1p component of pyruvate dehydrogenase complex, subunit of pyruvate dehydrogenase and pyruvate dehydrogenase multienzyme complex [KO:K00163] [EC:1.2.4.1]
B21_00113  aceF; dihydrolipoamide acetyltransferase / lipoate acetyltransferase, subunit of pyruvate dehydrogenase multienzyme complex [KO:K00627] [EC:2.3.1.12]
B21_01361  ydbK; predicted pyruvate:flavodoxin oxidoreductase [KO:K03737] [EC:1.2.7.1 1.2.7.-]
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
ebe00010  Glycolysis / Gluconeogenesis
ebe00053  Ascorbate and aldarate metabolism
ebe00061  Fatty acid biosynthesis
ebe00071  Fatty acid degradation
ebe00190  Oxidative phosphorylation
ebe00220  Arginine biosynthesis
ebe00250  Alanine, aspartate and glutamate metabolism
ebe00280  Valine, leucine and isoleucine degradation
ebe00350  Tyrosine metabolism
ebe00470  D-Amino acid metabolism
ebe00630  Glyoxylate and dicarboxylate metabolism
KO pathway
ko00020   
LinkDB

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