Enzyme Commission number

The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze.^[1] As a system of enzyme nomenclature, every EC number is associated with a recommended name for the corresponding enzyme-catalyzed reaction.

EC numbers do not specify enzymes but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number.^[2] Furthermore, through convergent evolution, completely different protein folds can catalyze an identical reaction (these are sometimes called non-homologous isofunctional enzymes)^[3] and therefore would be assigned the same EC number. By contrast, UniProt identifiers uniquely specify a protein by its amino acid sequence.^[4]

^ Webb, E. C. (1992). Enzyme nomenclature 1992: recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the nomenclature and classification of enzymes. Academic Press. ISBN 978-0-12-227164-9.
^ "ENZYME (Enzyme nomenclature database)". ExPASy. Archived from the original on 21 March 2019. Retrieved 24 April 2019.
^ Omelchenko MV, Galperin MY, Wolf YI, Koonin EV (2010). "Non-homologous isofunctional enzymes: a systematic analysis of alternative solutions in enzyme evolution". Biology Direct. 5 (1): 31. doi:10.1186/1745-6150-5-31. PMC 2876114. PMID 20433725.
^ Apweiler R, Bairoch A, Wu CH, Barker WC, Boeckmann B, Ferro S, Gasteiger E, Huang H, Lopez R, Magrane M, Martin MJ, Natale DA, O'Donovan C, Redaschi N, Yeh LS (Jan 2004). "UniProt: the Universal Protein knowledgebase". Nucleic Acids Research. 32 (Database issue): D115–9. doi:10.1093/nar/gkh131. PMC 308865. PMID 14681372.

[isbn0-12-227164-5-1] Webb, E. C. (1992). Enzyme nomenclature 1992: recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the nomenclature and classification of enzymes. Academic Press. ISBN 978-0-12-227164-9.

[expasy-2] "ENZYME (Enzyme nomenclature database)". ExPASy. Archived from the original on 21 March 2019. Retrieved 24 April 2019.

[pmid20433725-3] Omelchenko MV, Galperin MY, Wolf YI, Koonin EV (2010). "Non-homologous isofunctional enzymes: a systematic analysis of alternative solutions in enzyme evolution". Biology Direct. 5 (1): 31. doi:10.1186/1745-6150-5-31. PMC 2876114. PMID 20433725.

[pmid14681372-4] Apweiler R, Bairoch A, Wu CH, Barker WC, Boeckmann B, Ferro S, Gasteiger E, Huang H, Lopez R, Magrane M, Martin MJ, Natale DA, O'Donovan C, Redaschi N, Yeh LS (Jan 2004). "UniProt: the Universal Protein knowledgebase". Nucleic Acids Research. 32 (Database issue): D115–9. doi:10.1093/nar/gkh131. PMC 308865. PMID 14681372.

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