Citric acid cycle

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© IUBMB 2003


Note: The bold bond shows the carboxymethyl group originating from the acetyl-CoA.


The overall reaction is:

CH3-CO-S-CoA + H2O + GDP + Pi = 2 CO2 + 4 x 2H + HS-CoA + GTP


Cyanobacteria lack EC 1.2.4.2 oxoglutarate dehydrogenase (succinyl-transferring). Instead they convert 2-oxoglutarate to succinate semialdehye, see Zhang S, Bryant DA. The tricarboxylic acid cycle in cyanobacteria. Science 334 (2011) 1551-1553. [PMID: 22174252]
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stereochemistry of EC 2.3.3.1 citrate (Si)-synthase
oxo-acid dehydrogenase complex reactions
EC 1.1.1.37 malate dehydrogenase
EC 1.1.1.41 isocitrate dehydrogenase (NAD+)
EC 1.1.1.42 isocitrate dehydrogenase (NADP+)
EC 1.2.1.16 succinate-semialdehyde dehydrogenase [NAD(P)+]
EC 1.2.1.24 succinate-semialdehyde dehydrogenase (NAD+)
EC 1.2.1.79 succinate-semialdehyde dehydrogenase (NADP+)
EC 1.2.4.2 oxoglutarate dehydrogenase (succinyl-transferring)
EC 1.3.5.1 succinate dehydrogenase (ubiquinone)
EC 1.8.1.4 dihydrolipoamide dehydrogenase
EC 2.3.1.61 dihydrolipoyllysine-residue succinyltransferase
EC 2.3.3.1 citrate (Si)-synthase
EC 4.1.1.71 2-oxoglutarate decarboxylase
EC 4.2.1.2 fumarate hydratase
EC 4.2.1.3 aconitate hydratase
EC 6.2.1.4 succinate-CoA ligase (GDP-forming)