Enzyme Classification and Nomenclature

Abstract

The variety of different names that had been used for the same enzyme and the fact that some different enzymes were known by the same name necessitated the development of a rational system for their classification and nomenclature. The International Union of Biochemistry devised a system of classification that allows the unambiguous identification of enzymes in terms of the reactions they catalyse. This relies on a numerical system (the EC number) to class enzymes in groups according to the types of reaction catalysed and systematic naming that describes the chemical reaction involved. This is now in widespread use and the official list of enzymes classified can be found at ExplorEnz – The Enzyme Database ( http://www.enzyme‐database.org).

Key Concepts

  • Many enzymes have several alternative names and the same name has sometimes been used for different enzymes. This necessitates the use of an unambiguous naming system.
  • Enzymes are classified in the IUBMB Enzyme List according to the reactions they catalyse.
  • The EC number is a unique identifier for each enzyme classified according to this system.
  • Each enzyme has a short entry in the Enzyme List describing what it catalyses and some other key details.
  • Commonly used enzyme names may contain ambiguities and an Accepted name is provided to avoid this.
  • A Glossary is provided to relate compound names used by biochemists to those used by chemists.
  • Systematic names describe the catalysed reaction in more detail but can be cumbersome.
  • There are now over 5500 classified enzymes and the list is being continuously expanded and updated.
  • The official list is available at http://www.enzyme‐database.org/ – where searches by old names, or EC number are possible.

Keywords: enzymes; classification; nomenclature

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Further Reading

Alberty RA, Cornish‐Bowden A, Goldberg RN, et al. (2011) Recommendations for terminology and databases for biochemical thermodynamics. Biophysical Chemistry 155: 89–103.

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Copeland RA (2000) Enzymes: A Practical Introduction to Structure, Mechanism, and Data Analysis. New York: Wiley‐VCH Inc.

Kotera M, McDonald AG, Boyce S and Tipton KF (2008) Functional group and substructure searching as a tool in metabolomics. PLoS One 3 (2): e1537.

McDonald AG, Boyce S, Moss GP, et al. (2007) ExplorEnz: a MySQL database of the IUBMB enzyme nomenclature. BMC Biochemistry 27 (8): 14.

McDonald AG, Tipton KF and Boyce S (2009) Tracing metabolic pathways from enzyme data. Biochimica et Biophysica Acta 1794: 1364–1371.

Tipton KF, Armstrong RN, Bakker BM, et al. (2014) Standards for Reporting Enzyme Data: The STRENDA Consortium: what it aims to do and why it should be helpful. Perspectives in Science 1: 131–137.

Panico R, Richer J‐C and Powell WH (1994) A Guide to IUPAC Nomenclature of Organic Compounds. Oxford: Blackwell Science.

Webb EC (1993) Enzyme nomenclature: a personal retrospective. FASEB Journal 7: 1192–1194.

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McDonald, Andrew G, Boyce, Sinead, and Tipton, Keith F(Apr 2015) Enzyme Classification and Nomenclature. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000710.pub3]