Figure 2.

Thermodynamic properties of the reactions in iAF1260. (A) The distribution of estimated Δ_rG′^m values for the reactions in iAF1260. Δ_rG′^m could be estimated for 1996 reactions (96%) in the reconstruction. 64% of the represented reactions have a negative Δ_rG′^m, and 20% of the reactions have a Δ_rG′^m of approximately zero. This distribution of Δ_rG′^m values indicates that most reactions in the model are thermodynamically favorable at millimolar concentration conditions. (B) The range of possible Δ_rG′ values for the reactions in iAF1260. Δ_rG′ differs from Δ_rG′^o (orange diamonds) and Δ_rG′^m (black diamonds) due to variations in metabolite concentrations from the 1 M and 1 mM reference states, respectively. Metabolite concentrations typically range from 0.02 to 0.00001 M, resulting in a wide range of values for Δ_rG′ (blue error bars). Taking uncertainty into account, the range of possible values for Δ_rG′ can be extended (purple error bars). The Δ_rG′ ranges were used to assess the feasibility and reversibility of the reactions in iAF1260; reactions for which a positive Δ_rG′ is not possible are thermodynamically irreversible.