Enteropeptidase

Enterokinase is a peptidase expressed by cells on the border of the small intestine. Enterokinase activates trypsinogen, a zymogen, to trypsin, indirectly activating a number of pancreatic digestive enzymes.

Contrary to what its name suggests, enterokinase is not a kinase, since it activates its substrate by cleavage and not phosphorylation. Newer texts refer to this enzyme more appropriately as enteropeptidase.

Overview: trypsinogen + enterokinase → trypsin + octapeptide