KEGG   PATHWAY: pspi00020
Entry
pspi00020                   Pathway                                
Name
Citrate cycle (TCA cycle) - Pseudohongiella spirulinae
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
pspi00020  Citrate cycle (TCA cycle)
pspi00020

Module
pspi_M00009  Citrate cycle (TCA cycle, Krebs cycle) [PATH:pspi00020]
pspi_M00010  Citrate cycle, first carbon oxidation, oxaloacetate => 2-oxoglutarate [PATH:pspi00020]
pspi_M00011  Citrate cycle, second carbon oxidation, 2-oxoglutarate => oxaloacetate [PATH:pspi00020]
pspi_M00307  Pyruvate oxidation, pyruvate => acetyl-CoA [PATH:pspi00020]
Other DBs
GO: 0006099
Organism
Pseudohongiella spirulinae [GN:pspi]
Gene
PS2015_1485  Citrate synthase [KO:K01647] [EC:2.3.3.1]
PS2015_987  Aconitate hydratase 1 [KO:K01681] [EC:4.2.1.3]
PS2015_1886  bifunctional aconitate hydratase 2/2-methylisocitrate dehydratase [KO:K01682] [EC:4.2.1.3 4.2.1.99]
PS2015_2798  Isocitrate dehydrogenase [KO:K00031] [EC:1.1.1.42]
PS2015_604  Isocitrate dehydrogenase [KO:K00031] [EC:1.1.1.42]
PS2015_1490  2-oxoglutarate dehydrogenase E1 component [KO:K00164] [EC:1.2.4.2]
PS2015_2789  Dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex [KO:K00658] [EC:2.3.1.61]
PS2015_1491  dihydrolipoamide succinyltransferase [KO:K00658] [EC:2.3.1.61]
PS2015_1492  Dihydrolipoyl dehydrogenase [KO:K00382] [EC:1.8.1.4]
PS2015_1494  succinyl-CoA synthetase subunit alpha [KO:K01902] [EC:6.2.1.5]
PS2015_1493  succinyl-CoA synthetase subunit beta [KO:K01903] [EC:6.2.1.5]
PS2015_1488  succinate dehydrogenase flavoprotein subunit [KO:K00239] [EC:1.3.5.1]
PS2015_1489  Succinate dehydrogenase, iron-sulfur protein [KO:K00240] [EC:1.3.5.1]
PS2015_1486  Succinate dehydrogenase [KO:K00241]
PS2015_1487  succinate dehydrogenase [KO:K00242]
PS2015_2198  Fumarate hydratase class I, aerobic [KO:K01676] [EC:4.2.1.2]
PS2015_988  fumarate hydratase [KO:K01679] [EC:4.2.1.2]
PS2015_1201  Malate dehydrogenase [KO:K00024] [EC:1.1.1.37]
PS2015_1024  Pyruvate carboxylase subunit A [KO:K01959] [EC:6.4.1.1]
PS2015_1025  Pyruvate carboxylase subunit B (Biotin-containing) [KO:K01960] [EC:6.4.1.1]
PS2015_441  Phosphoenolpyruvate carboxykinase [KO:K01610] [EC:4.1.1.49]
PS2015_2274  Pyruvate dehydrogenase E1 component [KO:K00163] [EC:1.2.4.1]
PS2015_2273  Acetyltransferase component of pyruvate dehydrogenase complex [KO:K00627] [EC:2.3.1.12]
PS2015_1279  Branched-chain alpha-keto acid dehydrogenase subunit E2 [KO:K00627] [EC:2.3.1.12]
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
pspi00010  Glycolysis / Gluconeogenesis
pspi00053  Ascorbate and aldarate metabolism
pspi00061  Fatty acid biosynthesis
pspi00071  Fatty acid degradation
pspi00190  Oxidative phosphorylation
pspi00220  Arginine biosynthesis
pspi00250  Alanine, aspartate and glutamate metabolism
pspi00280  Valine, leucine and isoleucine degradation
pspi00350  Tyrosine metabolism
pspi00470  D-Amino acid metabolism
pspi00630  Glyoxylate and dicarboxylate metabolism
KO pathway
ko00020   
LinkDB

DBGET integrated database retrieval system