Overview of the different E. coli models. For simplicity we only show pathways. Cofactors etc. are suppressed. Metabolites contributing to the biomass are depicted in yellow. Pathways included in the E2 model are indicated in red. E1 contains the red and blue pathways only, while E0  incloses all reactions, including the non-colored pathways. A detailed listing of all models may be found in the Additional file 1.