EC number 194690 224810635 2008-07-10T14:52:51Z Broadbot 3410049 robot Adding: [[da:EC-nummer]] : ''This article is about the Enzyme Commission codes. For the European Commission system for coding chemicals, see [[EC-No]].'' The '''Enzyme Commission number''' ('''EC number''') is a [[numbering scheme|numerical classification]] scheme for [[enzyme]]s, based on the [[chemical reaction]]s they [[catalysis|catalyze]]. As a system of '''enzyme nomenclature''', every EC number is associated with a recommended name for the respective enzyme. Strictly speaking, 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. By contrast, [[UniProt]] identifiers uniquely specify a protein by its amino acid sequence.<ref>{{cite web | publisher = ExPASy | title = ENZYME (Enzyme nomenclature database) | url = http://www.expasy.org/enzyme/ | accessdate = 2006-03-14 }}</ref> ==Format of number== Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme. For example, the [[tripeptide aminopeptidase]]s have the code "EC 3.4.11.4", whose components indicate the following groups of enzymes: * ''EC 3'' enzymes are [[hydrolase]]s (enzymes that use [[water]] to break up some other molecule) * ''EC 3.4'' are hydrolases that act on [[peptide bond]]s * ''EC 3.4.11'' are those hydrolases that cleave off the amino-terminal [[amino acid]] from a [[polypeptide]] * ''EC 3.4.11.4'' are those that cleave off the amino-terminal end from a [[tripeptide]] ==Top level codes== {| class="wikitable" |+ Top-level EC numbers<ref>{{cite web | last = Moss | first = G.P. | title = Recommendations of the Nomenclature Committee | publisher = International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzymes by the Reactions they Catalyse | url = http://www.chem.qmul.ac.uk/iubmb/enzyme/ | accessdate = 2006-03-14}}</ref> |- ! Group ! Reaction catalyzed ! Typical reaction ! Enzyme example(s) with trivial name |- ! |EC 1<br />''[[Oxidoreductase]]s'' | To catalyze [[oxidation]]/reduction reactions; transfer of H and O atoms or [[electron]]s from one substance to another | AH + B → A + BH (<small>'''reduced'''</small>)<br /> A + O → AO (<small>'''oxidized'''</small>) | [[Dehydrogenase]], [[oxidase]] |- ! EC 2<br />''[[Transferase]]s'' | Transfer of a [[functional group]] from one substance to another. The group may be methyl-, acyl-, amino- or phosphate group | AB + C → A + BC | [[Transaminase]], [[kinase]] |- ! EC 3<br />''[[Hydrolase]]s'' | Formation of two products from a substrate by [[hydrolysis]] | AB + H<sub>2</sub>O → AOH + BH | [[Lipase]], [[amylase]], [[peptidase]] |- ! EC 4<br />''[[Lyase]]s'' | Non-hydrolytic addition or removal of groups from substrates. C-C, C-N, C-O or C-S bonds may be cleaved | RCOCOOH → RCOH + CO<sub>2</sub> | [[Decarboxylase]] |- ! EC 5<br />''[[Isomerase]]s'' | Intramolecule rearrangement, i.e. [[isomer|isomerization]] changes within a single molecule | AB → BA</td> | [[Isomerase]], [[mutase]] |- ! EC 6<br />''[[Ligase]]s'' | Join together two molecules by synthesis of new C-O, C-S, C-N or C-C [[covalent bond|bonds]] with simultaneous breakdown of [[Adenosine triphosphate|ATP]] | X + Y+ ATP → XY + ADP + Pi | [[Synthetase]] |} ==History== The enzyme nomenclature scheme was developed starting in [[1955]], when the International Congress of Biochemistry in [[Brussels]] set up an Enzyme Commission. The first version was published in [[1961]]. The current sixth edition, published by the [[International Union of Biochemistry and Molecular Biology]] in [[1992]], contains 3196 different enzymes. ==References== <references/> ==See also== * [[TC number]] (classification of membrane transport proteins) * [[List of enzymes]] {{Enzymes}} [[Category:Enzymes]] [[Category:Classification systems]] [[ar:رقم التصنيف الأنزيمي]] [[da:EC-nummer]] [[de:EC-Nummer]] [[es:Número EC]] [[fr:Nomenclature EC]] [[id:Nomor EC]] [[it:Classificazione EC]] [[ja:EC番号]] [[pl:Numer EC]] [[pt:Número EC]] [[ru:Шифр КФ]] [[tr:EC numarası]] [[zh:EC編號]]