Complementary Approach for Thermodynamic Analysis of Metabolic Pathways

An effective strategy comprising two steps is proposed to determine the thermodynamically dominant pathways in a metabolic network involving a number of reaction steps. In the first step, stoichiometrically feasible metabolic pathways are exhaustively identified through the flux balance analysis and the graph-theoretic method based on P-graphs. In the second step, thermodynamically dominant pathways are selected from these stoichiometrically feasible metabolic pathways on the basis of the Gibbs free energy change of reaction and the flux of every reaction step in the pathways. The proposed strategy is applied to an E. coli model for two cases, one for the maximal acetate production and the other for the maximal ethanol production, to demonstrate its profound efficacy.