EcoCyc: Encyclopedia of Escherichia coli Genes and Metabolism
EcoCyc is a bioinformatics database that describes the genome and the biochemical machinery of E. coli. The long-term goal of the project is to describe the molecular catalog of the E. coli cell, as well as the functions of each of its molecular parts, to facilitate a system-level understanding of E. coli.
 

MetaCyc: Metabolic Pathway Database
The MetaCyc metabolic pathway database contains pathways from over 150 different organisms. MetaCyc describes metabolic pathways, reactions, enzymes, and substrate compounds. The MetaCyc data were gathered from a variety of literature and on-line sources, and contain citations to the source of each pathway.