Table 1

Database cross-references in Reactome
Database	Protein	Gene	Small molecule	Activity	Compartment	Process

UniProt	X^a
Entrez Genes		X
ChEBI			X^a
GO				X^a	X^a	X^a
Ensembl		X
UCSC		X
KEGG		X	X
OMIM		X

^aCurated cross-references. ChEBI, Chemical Entities of Biological Interest; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; OMIM, Online Mendelian Inheritance in Man; UCSC, UCSC Genome Browser; UniProt, Universal Protein Resource.
Vastrik et al. Genome Biology 2007 8:R39 doi:10.1186/gb-2007-8-3-r39