Figure 2.  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 Download authors' original image