KEGG   PATHWAY: xla00020
Entry
xla00020                    Pathway                                
Name
Citrate cycle (TCA cycle) - Xenopus laevis (African clawed frog)
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
xla00020  Citrate cycle (TCA cycle)
xla00020

Module
xla_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:xla00020]
xla_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:xla00020]
xla_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:xla00020]
xla_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:xla00020]
xla_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:xla00020]
Other DBs
GO: 0006099
Organism
Xenopus laevis (African clawed frog) [GN:xla]
Gene
108696840  sdhb.L; succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial-like [KO:K00235] [EC:1.3.5.1]
108698673  dlst.L; dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex, mitochondrial [KO:K00658] [EC:2.3.1.61]
108700387  sdhc.S; succinate dehydrogenase cytochrome b560 subunit, mitochondrial [KO:K00236]
108703071  idh1.S; isocitrate dehydrogenase [NADP] cytoplasmic [KO:K00031] [EC:1.1.1.42]
108705521  [KO:K00627] [EC:2.3.1.12]
108705582  [KO:K01679] [EC:4.2.1.2]
108706503  suclg1.S; succinate--CoA ligase [ADP/GDP-forming] subunit alpha, mitochondrial [KO:K01899] [EC:6.2.1.4 6.2.1.5]
108707014  pck2.S; phosphoenolpyruvate carboxykinase [GTP], mitochondrial [KO:K01596] [EC:4.1.1.32]
108708533  sucla2.L; succinate--CoA ligase [ADP-forming] subunit beta, mitochondrial [KO:K01900] [EC:6.2.1.4 6.2.1.5]
108709827  cs.S; citrate synthase, mitochondrial-like [KO:K01647] [EC:2.3.3.1]
108711180  dld.L; dihydrolipoyl dehydrogenase, mitochondrial [KO:K00382] [EC:1.8.1.4]
108711283  idh3a.L; isocitrate dehydrogenase [NAD] subunit alpha, mitochondrial isoform X1 [KO:K00030] [EC:1.1.1.41]
108711446  idh2.L; isocitrate dehydrogenase [NADP], mitochondrial [KO:K00031] [EC:1.1.1.42]
108715122  [KO:K01958] [EC:6.4.1.1]
108716589  mdh1.L; malate dehydrogenase 1 L homeolog, cytoplasmic isoform mdh1 [KO:K00025] [EC:1.1.1.37]
121393055  [KO:K00161] [EC:1.2.4.1]
121400462  [KO:K00161] [EC:1.2.4.1]
121400464  [KO:K00161] [EC:1.2.4.1]
121400742  [KO:K00161] [EC:1.2.4.1]
121400745  [KO:K00161] [EC:1.2.4.1]
121400749  [KO:K00161] [EC:1.2.4.1]
379637  pck1.S; phosphoenolpyruvate carboxykinase 1 S homeolog [KO:K01596] [EC:4.1.1.32]
379844  pck1.L; cytosolic phosphoenolpyruvate carboxykinase 1 [KO:K01596] [EC:4.1.1.32]
379886  cs.L; citrate synthase, mitochondrial precursor [KO:K01647] [EC:2.3.3.1]
379939  sdhb.S; succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial precursor [KO:K00235] [EC:1.3.5.1]
380013  idh2.S; isocitrate dehydrogenase 2 (NADP+), mitochondrial S homeolog [KO:K00031] [EC:1.1.1.42]
380269  aco1.L; aconitase 1 L homeolog [KO:K01681] [EC:4.2.1.3]
380395  dlst.S; dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex, mitochondrial [KO:K00658] [EC:2.3.1.61]
380463  sdha.S; succinate dehydrogenase [ubiquinone] flavoprotein subunit B, mitochondrial precursor [KO:K00234] [EC:1.3.5.1]
380588  dld.S; dihydrolipoamide dehydrogenase S homeolog [KO:K00382] [EC:1.8.1.4]
398064  pdhb.L; pyruvate dehydrogenase E1 beta subunit L homeolog [KO:K00162] [EC:1.2.4.1]
398139  aco2.L; aconitase 2 L homeolog [KO:K01681] [EC:4.2.1.3]
398314  dlat.L; dihydrolipoamide S-acetyltransferase L homeolog [KO:K00627] [EC:2.3.1.12]
398811  pc.1.L; pyruvate carboxylase, gene 1 L homeolog [KO:K01958] [EC:6.4.1.1]
398872  mdh1.S; malate dehydrogenase 1 S homeolog, cytoplasmic isoform mdh1 [KO:K00025] [EC:1.1.1.37]
398946  sdha.L; succinate dehydrogenase [ubiquinone] flavoprotein subunit A, mitochondrial precursor [KO:K00234] [EC:1.3.5.1]
399021  ogdh.S; 2-oxoglutarate dehydrogenase, mitochondrial precursor [KO:K00164] [EC:1.2.4.2]
399424  pck2.L; phosphoenolpyruvate carboxykinase 2 (mitochondrial) L homeolog [KO:K01596] [EC:4.1.1.32]
399452  pdhb.S; pyruvate dehydrogenase E1 beta subunit S homeolog [KO:K00162] [EC:1.2.4.1]
443751  mdh2.S; malate dehydrogenase 2 S homeolog [KO:K00026] [EC:1.1.1.37]
443821  idh3b.S; isocitrate dehydrogenase (NAD(+)) 3 beta S homeolog [KO:K00030] [EC:1.1.1.41]
444121  ogdh.L; oxoglutarate dehydrogenase L homeolog [KO:K00164] [EC:1.2.4.2]
444419  idh3a.S; isocitrate dehydrogenase (NAD(+)) 3 alpha S homeolog [KO:K00030] [EC:1.1.1.41]
444551  idh3g.S; isocitrate dehydrogenase (NAD(+)) 3 gamma S homeolog [KO:K00030] [EC:1.1.1.41]
444692  aco2.S; aconitase 2 S homeolog [KO:K01681] [EC:4.2.1.3]
446263  mdh2.L; malate dehydrogenase 2 L homeolog [KO:K00026] [EC:1.1.1.37]
446473  pdha1.L; pyruvate dehydrogenase E1 alpha 1 subunit L homeolog [KO:K00161] [EC:1.2.4.1]
447333  sucla2.S; succinate-CoA ligase, ADP-forming, beta subunit S homeolog [KO:K01900] [EC:6.2.1.4 6.2.1.5]
447370  ogdhl.L; 2-oxoglutarate dehydrogenase-like, mitochondrial precursor [KO:K00164] [EC:1.2.4.2]
447434  pdha1.S; pyruvate dehydrogenase E1 alpha 1 subunit S homeolog [KO:K00161] [EC:1.2.4.1]
494586  sdhd.S; succinate dehydrogenase [ubiquinone] cytochrome b small subunit A, mitochondrial [KO:K00237]
494713  idh1.L; isocitrate dehydrogenase 1 [KO:K00031] [EC:1.1.1.42]
494796  suclg1.L; succinate-CoA ligase, alpha subunit L homeolog [KO:K01899] [EC:6.2.1.4 6.2.1.5]
495086  acly.S; ATP citrate lyase S homeolog [KO:K01648] [EC:2.3.3.8]
495316  acly.L; uncharacterized protein LOC495316 [KO:K01648] [EC:2.3.3.8]
496372  sdhd.L; succinate dehydrogenase [ubiquinone] cytochrome b small subunit B, mitochondrial [KO:K00237]
734975  suclg2.L; succinate-CoA ligase, GDP-forming, beta subunit L homeolog [KO:K01900] [EC:6.2.1.4 6.2.1.5]
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
xla00010  Glycolysis / Gluconeogenesis
xla00053  Ascorbate and aldarate metabolism
xla00061  Fatty acid biosynthesis
xla00062  Fatty acid elongation
xla00071  Fatty acid degradation
xla00190  Oxidative phosphorylation
xla00220  Arginine biosynthesis
xla00250  Alanine, aspartate and glutamate metabolism
xla00280  Valine, leucine and isoleucine degradation
xla00350  Tyrosine metabolism
xla00470  D-Amino acid metabolism
xla00630  Glyoxylate and dicarboxylate metabolism
KO pathway
ko00020   

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