Enteropeptidase 2369888 217910207 2008-06-08T07:38:01Z 220.245.194.124 {{protein |Name=protease, serine, 7 (enteropeptidase) |caption=[[X-ray crystallography|Crystal structure]] of Enteropeptidase with an [[inhibitor]] |image=1EKB.png |width= |HGNCid=9490 |Symbol=PRSS7 |AltSymbols= |EntrezGene=5651 |OMIM=606635 |RefSeq=NM_002772 |UniProt=P98073 |PDB= |ECnumber= |Chromosome=21 |Arm=q |Band=21 |LocusSupplementaryData= }} '''Enteropeptidase''' (previously called '''enterokinase''') is an [[enzyme]] involved in human [[digestion]]. It is produced by cells in the duodenum wall, and is secreted from duodenum's glands, the [[crypts of Lieberkühn]], whenever ingested food enters the duodenum from the stomach. Enteropeptidase has the critical job of turning [[trypsinogen]] (a [[zymogen]]) to [[trypsin]], indirectly activating a number of [[pancreas|pancreatic]] digestive enzymes. Enteropeptidase is a [[serine protease]] [[enzyme]] ({{EC number|3.4.21.9}}). Enteropeptidase is a part of the [[Chymotrypsin]]-clan of serine proteases, and is structurally similar to these proteins. ==Reaction== The reaction [[catalysis|catalysed]] by Enteropeptidase: trypsinogen → trypsin + octapeptide Enteropeptidase cleaves after Lysine if the Lys is preceded by four Asp and not followed by a Pro. <ref>{{cite web|url=http://www.neb.com/nebecomm/products/productP8070.asp|title=Enterokinase, light chain (P8070), Proteases, NEB|accessdate=2007-10-04}}</ref> ==Nomenclature== Despite its older name of ''enterokinase'', the enzyme is not a [[kinase]]. This is because enteropeptidase alters the degree of enzymatic activity its substrate expresses though a proteolytic cleavage reaction. A [[kinase]] would do the same by [[phosphorylation]] reaction. ==Genetics== Enteropeptidase is encoded by the ''PRSS7'' (serine protease-7 gene) or ''ENTK'' gene on the [[chromosome 21|21st chromosome]] (21q21). Isolated cases of enteropeptidase deficiency have been reported.<ref>{{cite journal |author=Holzinger A, Maier EM, Bück C, ''et al'' |title=Mutations in the proenteropeptidase gene are the molecular cause of congenital enteropeptidase deficiency |journal=Am. J. Hum. Genet. |volume=70 |issue=1 |pages=20–5 |year=2002 |pmid=11719902 |doi=}}</ref> ==References== <references/> ==External links== * {{MeshName|Enteropeptidase}} [[Category:EC 3.4.21]] {{hydrolase-stub}} {{Serine endopeptidases}} [[de:Enteropeptidase]] [[nl:Enterokinase]] [[ja:エンテロキナーゼ]] [[sl:Enteropeptidaza]]