Enzyme Nomenclature and Classification

A detailed presentation of enzyme nomenclature and classification can be obtained from the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology at the website http //www.chem.qmul.ac.uk/iubmb/ enzyme/. 

Based on the International Union of Biochemistry and Molecular Biology s Enzyme Nomenclature and Classification (Webb, 1992), lignocellulose-degrading enzymes belong to... 

Walker, C.H. (1989). The development of an improved system of nomenclature and classification of esterases. In E. Reiner, W.N. Aldridge, and F.C.G. Hoskin (Eds.) Enzymes Elydrolysing Organophosphorous Compounds, Chichester Ellis Harwood. 53-64. 

IUPAC and IUB (1972) Enzyme Nomenclature Recommendations of the Commission on Biochemical Nomenclature on the Nomenclature and Classification of Enzymes together with their Units and the Symbols of Enzyme Kinetics. Elsevier, Amsterdam. 

Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Enzyme Nomenclature Recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzyme-Catalysed Reactions. Published in Enzyme Nomenclature 1992 [Academic Press, San Diego, California, ISBN 0-12-227164-5 (hardback), 0-12-227165-3 (paperback)] with Supplement 1 (1993), Supplement 2 (1994), Supplement 3 (1995), Supplement 4 (1997), and Supplement 5 (in Eur.J. Biochem. 1994, 223, 1—5 Eur. J. Biochem. 1995, 232, 1—6 Eur.J. Biochem. 1996, 237, 1—5 Eur. J. Biochem. 1997, 250, 1—6, and Eur.J. Biochem. 1999, 264, 610—650, respectively) [Copyright lUBMB] and online at http //www.chem.qmuLac.uk/iubmb/enzyme/index.html). 

Flavoenzymes constitute about 2% of all biological catalysts and are classified in several ways. One classification is based on EC number (enzyme nomenclature) and refers to the type of reaction catalyzed. More sophisticated classifications concern the inclusion of sequence, fold, and function. Historically, a distinction is made between simple and complex flavoenzymes (4). The latter proteins contain besides flavin other cofactors like heme, tetrahydrobiopterin, and metal ions. 

Most of the names used in this Chapter for enzymes are those recommended by the Commission on the Nomenclature and Classification of Enzymes, in Comprehensive Biochemistry, M. Florkin and E. H. Stotz, eds., Elsevier, Amsterdam, 3rd Edition, 1973, Vol. 13. However, the Editors have altered some of the names to conform with established nomenclature for carbohydrates. 

Nomenclature Committee, I.E. 1978. Recommendations of the Nomenclature Committee of lUB on the Nomenclature and Classification of Enzymes. New York Academic Press, 1979. 

Webb, E. C. 1984. Enzyme nomenclature 1984 Recommendations of the nomenclature committee of the international union of biochemistry on the nomenclature and classification of enzyme-catalyzed reactions. Orlando, FL Academic Press. 

I.U.B. definitions were indicated. Objections were made that the minute is not an S.I. unit. It was proposed to define enzyme activity by a catalytic amount (katal) of a system that catalyzes exactly as many cycles per second of a reaction scheme as there are atoms in 0.012 kg of the pure nuclide 12C. This point of view was adopted and recommended by the commission of Biochemical Nomenclature of I.U.B. in 1972, as appearing in Nomenclature and Classification of Enzymes, together with their units and symbols (revision and extension of recommendations of 1962 and 1964, Elsevier, Amsterdam, 1972). The katal was proposed as a unit of enzymic activity to be used instead of the earlier unit, and this recommendation was approved by the general assembly of the I.U.B. Congress at Stockholm, July 1973. 

Molecular Biology on the nomenclature and classification of enzyme-catalyzed reactions by Nomenclature Committee of the International Union of Biochemistry and Molecular Biology, available online at www.chem.qmul.ac.uk/iubmb/ enzyme/ NC-IUBMB, Symbolism and terminology in enzyme kinetics Nomenclature Committee of the International Union of Biochemistry, available online at www.chem.qmul.ac.uk/iubmb/kinetics/ prepared by G.P. Moss department of chemistry. Queen Mary University of London, U.K., 1981. 

The EC numbers of enzymes are from the Recommendations (1984) of the Nomenclature Committee of the International Union of Biochemistry on the Nomenclature and Classification of Enzyme-Catalysed Reactions ( Enzyme Nomenclature , Academic Press, 1984). 

Standard abbreviations used in both the biochemical and chemical literature have been employed in the text and are listed in the Biochemical Journal publication, Policy of the Journal and Instructions to Authors issued by the Biochemical Society, London, 1972. Wherever possible enzymes have been named at the first mention by use of the EC (Enzyme Commission) numbers (Recommendations of the International Union of Biochemistry on the nomenclature and classification of Enzymes, Elsevier, Amsterdam, 1965). 

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification. 

Enzyme Nomenclature. The number of enzymes known exceeds two thousand. A system of classification and nomenclature is required to identify them unambiguously. During the nineteenth century, it was the practice to identify enzymes by adding the suffix -in to the name of their source. Names such as papain, ftcin, trypsin, pepsin, etc, are still in use. However, this system does not give any indication of the nature of the reaction catalyzed by the enzyme or the type of substrate involved. 

International Union of Biochemistry and Molecular Biology Nomenclature Committee, 1992. Enzyme Nomenclature. New York Academic Press. A reference volume and glossary on die official classification and nomenclature of enzymes. 

Classification of Enzymes. A systematic classification and nomenclature has been established by the Commission on Enzymes of the International Union of Biochemistry (6), which divides enzymes into six general groups ... 

The classification adopted by the Nomenclature Committee (NC) of the International Union of Biochemistry and Molecular Biology (IUBMB) divides peptidases into classes and subclasses according to the positional specificity in the cleavage of the peptide link of the substrate. The last publication of the complete printed version of the Enzyme Nomenclature was in 1992 [1][2], but a constantly updated version with supplements is available on the World Wide Web at http //www.chem.qmul.ac.uk/iubmb/enzyme/. Similarly, all available Protein Data Bank (PDB) entries classified as recommended by the NC-IUBMB can be found on the WWW at http //www.bio-chem.ucl.ac.uk/bsm/enzymes/. 

---