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]]