BioCyc (SRI) This link opens in a new window
BioCyc is a collection of 7613 Pathway/Genome Databases (PGDBs), plus software tools for understanding their data. Tier 1 databases have received at least one person-year of literature-based curation, and are the most accurate. EcoCyc and MetaCyc have each received more than 20 person-years of curation.
Tier 2 and Tier 3 databases contain computationally predicted metabolic pathways, predictions as to which genes code for missing enzymes in metabolic pathways, and predicted operons.-From Publisher