Each database entry in KEGG is identified by the form of ‘db:entry’ where ‘db’ is the database name and ‘entry’ is the entry identifier. With the new version of the DBGET database retrieval system (16) the db prefix is no longer necessary, because the entry identifiers are unique across all the KEGG databases. For example, C00022 is sufficient rather than cpd:C00022. See more details at the KEGG identifiers page (http://www.genome.jp/kegg/kegg3.html). This simple form can be used to retrieve individual database entries, pathway maps and BRITE hierarchies by the REST-based URLs (http://www.genome.jp/kegg/docs/weblink.html) at the KEGG web site.
