Entry
Name
Citrate cycle (TCA cycle) - Mycobacterium canettii CIPT 140070008
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
BRITE hierarchy
Pathway map
Ortholog table
Module
mcv_M00010 Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:mcv00020 ]
mcv_M00011 Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:mcv00020 ]
Other DBs
Organism
Mycobacterium canettii CIPT 140070008 [GN:
mcv ]
Gene
BN43_10079 icd; Putative isocitrate dehydrogenase [NADP] Icd2 (oxalosuccinate decarboxylase) (IDH) (NADP+-specific ICDH) (IDP) [KO:K00031 ] [EC:1.1.1.42 ]
BN43_10501 lpd; Dihydrolipoamide dehydrogenase Lpd (lipoamide reductase (NADH)) (lipoyl dehydrogenase) (dihydrolipoyl dehydrogenase) (diaphorase) [KO:K00382 ] [EC:1.8.1.4 ]
BN43_10280 Putative succinate dehydrogenase [iron-sulfur subunit] (succinic dehydrogenase) [KO:K00239 ] [EC:1.3.5.1 ]
BN43_10279 Putative succinate dehydrogenase [iron-sulfur subunit] (succinic dehydrogenase) [KO:K00240 ] [EC:1.3.5.1 ]
BN43_60338 sdhB; Putative succinate dehydrogenase (iron-sulphur protein subunit) SdhB (succinic dehydrogenase) (fumarate reductase) (fumarate dehydrogenase) (fumaric hydrogenase) [KO:K00240 ] [EC:1.3.5.1 ]
BN43_60335 sdhC; Putative succinate dehydrogenase (cytochrome B-556 subunit) SdhC (Succinic dehydrogenase) (Fumarate reductase) (Fumarate dehydrogenase) (Fumaric hydrogenase) [KO:K00241 ]
BN43_60336 sdhD; Putative succinate dehydrogenase (hydrophobic membrane anchor subunit) SdhD (Succinic dehydrogenase) (Fumarate reductase) (Fumarate dehydrogenase) (Fumaric hydrogenase) [KO:K00242 ]
BN43_30679 frdA; Putative fumarate reductase [flavoprotein subunit] FrdA (fumarate dehydrogenase) (fumaric hydrogenase) [KO:K00244 ] [EC:1.3.5.1 ]
BN43_30681 frdC; Putative fumarate reductase [membrane anchor subunit] FrdC (fumarate dehydrogenase) (fumaric hydrogenase) [KO:K00246 ]
BN43_40542 mqo; Putative malate:quinone oxidoreductase Mqo (malate dehydrogenase [acceptor]) [KO:K00116 ] [EC:1.1.5.4 ]
BN43_31484 aceE; Putative pyruvate dehydrogenase E1 component AceE (pyruvate decarboxylase) (pyruvate dehydrogenase) (pyruvic dehydrogenase) [KO:K00163 ] [EC:1.2.4.1 ]
BN43_31450 dlaT; DlaT, dihydrolipoamide acyltransferase, E2 component of pyruvate dehydrogenase [KO:K00627 ] [EC:2.3.1.12 ]
Compound
C05125 2-(alpha-Hydroxyethyl)thiamine diphosphate
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
mcv00053 Ascorbate and aldarate metabolism
mcv00250 Alanine, aspartate and glutamate metabolism
mcv00280 Valine, leucine and isoleucine degradation
mcv00630 Glyoxylate and dicarboxylate metabolism
KO pathway
LinkDB
All DBs