What is ChEBI?

ChEBI is a freely available, open source bioinformatics and cheminformatics resource that provides manually annotated information on 'small' chemical entities – constitutionally or isotopically distinct atoms, molecules, ion pairs, radicals, radical ions, complexes, conformers, or anything else that is a distinguishable entity (Figure 1).

In biology, metabolites are a typical example of small molecules. Molecules directly encoded by the genome (e.g. nucleic acids, proteins and peptides derived from proteins by cleavage) are not as a rule included in ChEBI.

The ChEBI homepage

Figure 1 The ChEBI homepage is easily accessible by clicking on the ChEBI Link in the Chemical biology panel on the EBI services page

ChEBI focuses on nomenclature endorsed by the International Union of Pure and Applied Chemistry (IUPAC) and the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). A major feature of ChEBI is that it includes a Chemical Ontology  a form of classification to specify relationships between molecular entities or classes of entities and their parents and/or children in a structured way.