A schematic diagram of central metabolism for E. coli. The network map is made based on our previous experiments. The numbers in the figure are those of reactions shown in Table 1. The gene name is representative of the genes related to the reaction. The metabolites indicated by squares, i.e., B (biomass), Glc_ext (environmental glucose) and Acetate_ext (environmental acetate), are external. All other metabolites, enclosed by rounded rectangles, are internal.