Enteropeptidase
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Enteropeptidase | |
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![]() Crystal structure of Enteropeptidase with an inhibitor |
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protein type: | Serine protease |
Functions: | digestion |
Domains: | serine protease domain |
Diseases: |
Enteropeptidase or 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 pancreatic digestive enzymes.
Enteropeptidase is a serine protease enzyme (EC 3.4.21.9). Enteropeptidase is a part of the Chymotrypsin-clan of serine proteases, and is structurally similar to these proteins.
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[edit] Reaction
The reaction catalysed by Enteropeptidase:
trypsinogen → trypsin + octapeptide
[edit] Nomenclature
Despite its older name of enterokinase, the enzyme is not a kinase, since it activates its substrate by cleavage and not phosphorylation.
[edit] Genetics
Enteropeptidase is encoded by the PRSS7 (serine protease-7 gene) or ENTK gene on the 21st chromosome (21q21).
Isolated cases of enterokinase deficiency have been reported (OMIM).
[edit] External link
Trypsin - Chymotrypsin - Elastase (Neutrophil, Pancreatic) - Enteropeptidase
Acrosin - Pronase - Proprotein convertases (1, 2) - Subtilisin/Furin
Immune (Chymase, Granzyme, Tryptase, Proteinase 3/Myeloblastin) - Venombin (Ancrod, Batroxobin)
Complement system: Factor B - Factor D - Factor I - MASP (MASP1, MASP2)
Coagulation factors: Thrombin - Factor VIIa - Factor IXa - Factor Xa - Factor XIa - Factor XIIa - Kallikrein (PSA) - Fibrinolysis: Plasmin - Tissue plasminogen activator - Urinary plasminogen activator