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Review
. 2023 May;290(9):2214-2231.
doi: 10.1111/febs.16274. Epub 2022 Jan 3.

Enzyme nomenclature and classification: the state of the art

Andrew G McDonald  1 , Keith F Tipton  1
Affiliations
Free article
Review

Enzyme nomenclature and classification: the state of the art

Andrew G McDonald et al. FEBS J. 2023 May.
Free article

Abstract

The IUBMB enzyme classification system, available at the IUBMB ExplorEnz website, uses a four-component number (the EC number) that identifies an enzyme in terms of reaction catalysed. There were originally six recognized groups of enzymes: Oxidoreductases (EC 1), Transferases (EC 2), Hydrolases (EC 3), Lyases (EC 4), Isomerases (EC 5) and Ligases (EC 6). Of these, the lyases, which are defined as 'enzymes that cleave C-C, C-O, C-N and other bonds by means other than by hydrolysis or oxidation', present particular recognition and classification problems. Recently, a new class, the Translocases (EC 7), has been added, which incorporates enzymes that catalyse the movement of ions or molecules across membranes or their separation within membranes. A new subclass of the isomerases has also been included for those enzymes that alter the conformations of proteins and nucleic acids. Newly reported enzymes are being regularly added to the list after validation and where new information affects the classification of an existing entry, a new EC number is created, but the old one is not reused.

Keywords: EC number; ExplorEnz; IUPAC names; macromolecular isomerases; translocases.

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References

    1. Fujiyoshi K, Bruford EA, Mroz P, Sims CL, O’Leary TJ, Lo AWI, Chen N, Patel NR, Patel KP, Seliger B et al. (2021) Opinion: standardizing gene product nomenclature-a call to action. Proc Natl Acad Sci USA 118, e2025207118.
    1. Strauss BS (2016) Biochemical genetics and molecular biology: the contributions of george beadle and edward tatum. Genetics 203, 13-20.
    1. Hoffmann-Ostenhof O (2006) Suggestions for a More Rational Classification and Nomenclature of Enzymes. In Advances in Enzymology - and Related Areas of Molecular Biology (Nord FF, ed), pp. 219-260. John Wiley & Sons Inc, Hoboken, NJ, USA.
    1. Dixon M & Webb EC (1958) Enzymes. Longman, London.
    1. Report of the Commission on Enzymes of the International Union of Biochemistry (1961) IUB Symposium Series, Vol. 20. Pergamon Press, New York and Oxford (1961) In IUB Symposium Series Pergamon Press, New York and Oxford.

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