Figure 1.

Numbers of metabolites (red bars) and chemical formulae (black bars) in the MetaCyc database present only in a specific number of reactions (A) or pathways (B). Numbers of metabolites (red bars) and chemical formulae (black bars) in the KEGG database present only in a specific number of reactions (C). Metabolites present in reactions not linked to any pathway in MetaCyc were not taken into account for panel B. A large number of metabolites and chemical formulae are unique, thus are associated with a single reaction or pathway.

Bowen et al. BMC Genomics 2011 12(Suppl 1):S6   doi:10.1186/1471-2164-12-S1-S6