Components of the TCA cycle reaction network

Charges for all of the references species in Table 6.1 are indicated using superscripts, even when the charge is zero. This notation distinguishes biochemical reactants (for example ACCOA) from references species (for example ACCOA0). 

We have chosen to use C032- as a reference species in reaction numbers 1, 4, and 5. Therefore the apparent thermodynamic properties of these reactions will be calculated in terms of the biochemical reactant XCO2. (See Section 2.6 for a discussion on the treatment of CO2 in biochemical reactions.) 

The eleventh reaction (aspartate aminotransferase) serves as a shortcut through the cycle, generating oxaloacetate and glutamate directly from a-ketoglutarate and glutamate. 

The source of ACCOA for citrate synthase (reaction 2) is the oxidation of carbohydrate, fatty acid, and amino acid molecules. The COAS generated by citrate synthase is used in the oxidation of substrates (such as pyruvate via pyruvate 

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