EC number
The EC numbers ( Enzyme Commission numbers ) form a numerical classification system for enzymes . Each EC number consists of four numbers separated by dots. Strictly speaking, it is not the enzyme itself that is categorized, but the reaction it catalyzes. It can happen that enzymes that are not related to each other and that catalyze the same reaction are assigned the same EC number.
Format of the classification
The classification becomes progressively more specific from left to right. The EC number of the enzyme tripeptide aminopeptidase ( EC 3.4.11.4 ) is composed as follows:
- EC 3.-.-.- : hydrolase
- EC 3.4.-.- : peptidase ( hydrolysis of a peptide bond )
- EC 3.4.11.- : aminopeptidase
- EC 3.4.11.4 : tripeptide aminopeptidase (catalyzes the cleavage of an amino-terminal amino acid from a tripeptide )
Individual evidence
- ^ GP Moss: Recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzymes by the Reactions they Catalyse . International Union of Biochemistry and Molecular Biology . Retrieved December 23, 2010.
Web links
- ExplorEnz - database of the of the IUBMB Enzyme Nomenclature List. Andrew McDonald (School of Biochemistry & Immunology, Trinity College, Dublin 2, Ireland), accessed February 12, 2016 .