Table 1.

Sources of different types of terms in the BioLexicon

Semantic type	Resources	Semantic type	Resources
Cell	Cell ontology	Nucleic Acid Region	Sequence Ontology (Region)
Cell Component	Gene Ontology (GO:0005575 cellular component)	Operon	RegulonDB, ODB
Chemical	CHEBI (IMR:0000947 chemical)	Organism	NCBI Species
Disease	OMIM	Transcription Factor-Binding-Site	Sequence Ontology
Enzyme	Enzyme Nomenclature	Protein	BioThesaurus
Gene	BioThesaurus	Protein Complex	Corum database
Ligand	IMR - INOH Protein name/family name ontology	Protein Domain	InterPro
Nuclear Receptor	Gene ontology (GO:0004879 ligand-dependent nuclear receptor activity)	Transcription Regulator	RegulonDB, TransFac, Gene Ontology Annotation

Each semantic type included in the BioLexicon is shown, together with resource(s) from which it has been extracted. In the case of large resources containing several types of terms (e.g., the Gene Ontology), the exact category of the extracted terms within the source resource is shown, together with an identifier for that category, if available.