The KEGG reference pathways, BRITE functional hierarchies, and KEGG modules are represented in a general way to be applicable to all organisms. The KEGG Orthology (KO) system is the basis for this representation, consisting of manually defined ortholog groups that correspond to KEGG pathway nodes, BRITE hierarchy nodes, and KEGG module components.
Nucleic acids research 2004;
The KEGG resource for deciphering the genome.
Kanehisa M , Goto S , Kawashima S , Okuno Y , Hattori M .