enterokinaasin

Enterokinase, also known as enteropeptidase, is a digestive enzyme produced by cells in the duodenum, the first section of the small intestine. Its primary function is to initiate the activation of pancreatic zymogens, which are inactive precursors of digestive enzymes. Specifically, enterokinase cleaves the N-terminal activation peptide from trypsinogen, converting it into its active form, trypsin. Trypsin then plays a crucial role in activating other pancreatic proteases, such as chymotrypsinogen, proelastase, and procarboxypeptidase, as well as activating more trypsinogen in a positive feedback loop. This cascade is essential for the efficient digestion of proteins in the small intestine.

The enzyme is synthesized as an inactive precursor, proenterokinase, and secreted into the duodenal lumen. Its activity is highly specific, primarily targeting the cleavage site on trypsinogen. While its main role is in protein digestion, enterokinase also has implications in other physiological processes. Mutations in the gene encoding enterokinase can lead to congenital enterokinase deficiency, a rare disorder characterized by severe protein malnutrition, failure to thrive, and anemia due to impaired protein digestion and subsequent nutrient malabsorption. In research and clinical settings, enterokinase is also used as a fusion tag in recombinant protein production to facilitate the specific cleavage and release of target proteins.