KEGG   PATHWAY: mmu00020
mmu00020                    Pathway                                

Citrate cycle (TCA cycle) - Mus musculus (mouse)
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
mmu00020  Citrate cycle (TCA cycle)

mmu_M00003  Gluconeogenesis, oxaloacetate => fructose-6P [PATH:mmu00020]
mmu_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:mmu00020]
mmu_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:mmu00020]
mmu_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:mmu00020]
mmu_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:mmu00020]
Other DBs
GO: 0006099
Mus musculus (mouse) [GN:mmu]
12974  Cs; citrate synthase [KO:K01647] [EC:]
71832  Csl; citrate synthase like [KO:K01647] [EC:]
104112  Acly; ATP citrate lyase [KO:K01648] [EC:]
11429  Aco2; aconitase 2, mitochondrial [KO:K01681] [EC:]
11428  Aco1; aconitase 1 [KO:K01681] [EC:]
15926  Idh1; isocitrate dehydrogenase 1 (NADP+), soluble [KO:K00031] [EC:]
269951  Idh2; isocitrate dehydrogenase 2 (NADP+), mitochondrial [KO:K00031] [EC:]
15929  Idh3g; isocitrate dehydrogenase 3 (NAD+), gamma [KO:K00030] [EC:]
67834  Idh3a; isocitrate dehydrogenase 3 (NAD+) alpha [KO:K00030] [EC:]
170718  Idh3b; isocitrate dehydrogenase 3 (NAD+) beta [KO:K00030] [EC:]
243996  4933405O20Rik; RIKEN cDNA 4933405O20 gene [KO:K00030] [EC:]
18293  Ogdh; oxoglutarate (alpha-ketoglutarate) dehydrogenase (lipoamide) [KO:K00164] [EC:]
239017  Ogdhl; oxoglutarate dehydrogenase-like [KO:K00164] [EC:]
78920  Dlst; dihydrolipoamide S-succinyltransferase (E2 component of 2-oxo-glutarate complex) [KO:K00658] [EC:]
13382  Dld; dihydrolipoamide dehydrogenase [KO:K00382] [EC:]
56451  Suclg1; succinate-CoA ligase, GDP-forming, alpha subunit [KO:K01899] [EC:]
20917  Suclg2; succinate-Coenzyme A ligase, GDP-forming, beta subunit [KO:K01900] [EC:]
20916  Sucla2; succinate-Coenzyme A ligase, ADP-forming, beta subunit [KO:K01900] [EC:]
66945  Sdha; succinate dehydrogenase complex, subunit A, flavoprotein (Fp) [KO:K00234] [EC:]
67680  Sdhb; succinate dehydrogenase complex, subunit B, iron sulfur (Ip) [KO:K00235] [EC:]
66052  Sdhc; succinate dehydrogenase complex, subunit C, integral membrane protein [KO:K00236]
66925  Sdhd; succinate dehydrogenase complex, subunit D, integral membrane protein [KO:K00237]
14194  Fh1; fumarate hydratase 1 [KO:K01679] [EC:]
17449  Mdh1; malate dehydrogenase 1, NAD (soluble) [KO:K00025] [EC:]
17448  Mdh2; malate dehydrogenase 2, NAD (mitochondrial) [KO:K00026] [EC:]
18563  Pcx; pyruvate carboxylase [KO:K01958] [EC:]
18534  Pck1; phosphoenolpyruvate carboxykinase 1, cytosolic [KO:K01596] [EC:]
74551  Pck2; phosphoenolpyruvate carboxykinase 2 (mitochondrial) [KO:K01596] [EC:]
18597  Pdha1; pyruvate dehydrogenase E1 alpha 1 [KO:K00161] [EC:]
18598  Pdha2; pyruvate dehydrogenase E1 alpha 2 [KO:K00161] [EC:]
68263  Pdhb; pyruvate dehydrogenase (lipoamide) beta [KO:K00162] [EC:]
235339  Dlat; dihydrolipoamide S-acetyltransferase (E2 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)
mmu00010  Glycolysis / Gluconeogenesis
mmu00053  Ascorbate and aldarate metabolism
mmu00061  Fatty acid biosynthesis
mmu00062  Fatty acid elongation
mmu00071  Fatty acid degradation
mmu00190  Oxidative phosphorylation
mmu00220  Arginine biosynthesis
mmu00250  Alanine, aspartate and glutamate metabolism
mmu00280  Valine, leucine and isoleucine degradation
mmu00350  Tyrosine metabolism
mmu00471  D-Glutamine and D-glutamate metabolism
mmu00630  Glyoxylate and dicarboxylate metabolism
KO pathway

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