Editing Enzyme Commission number (section)

==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.  Preliminary EC numbers exist and have an 'n' as part of the fourth (serial) digit (e.g. EC 3.5.1.n3).<ref name="expasy"/>

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 hydrolases (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]]