Metabolic networks in the EMRS. A) Metabolic reaction map of E. coli, where endogenous metabolites are depicted as light blue nodes connected by edges representing reactions; B) Retrosynthetic map containing reachable compounds in the E. coli EMRS through exogenous reactions, where exogenous metabolites are represented by pink nodes connected through reactions (thin edges) to the E. coli network. There are 966 endogenous and 2338 exogenous compounds, respectively, that can be reached through reactions in the EMRS. There are 4,344 edges connecting endogenous compounds and 8,931 edges leading to exogenous compounds.
Carbonell et al. BMC Systems Biology 2011 5:122 doi:10.1186/1752-0509-5-122