Activation of Trypsinogen to Trypsin

Trypsinogen is converted into its active form trypsin in the presence of:

Correct Answer: Enterokinase

Trypsinogen (inactive) is converted to trypsin (active) by enterokinase (enteropeptidase), an enzyme secreted by the brush border cells (enterocytes) of the duodenum.

Key Steps

• Trypsinogen is secreted by the acinar cells of the pancreas as an inactive zymogen to prevent self-digestion (pancreatitis).
• Upon entry into the duodenum, enterokinase cleaves a hexapeptide from the N-terminus of trypsinogen → trypsin.
• Trypsin itself can then activate more trypsinogen (autocatalysis) and also activate other pancreatic zymogens: chymotrypsinogen → chymotrypsin, proelastase → elastase, procarboxypeptidase → carboxypeptidase.

Clinical Significance

• If trypsinogen is prematurely activated within the pancreas (e.g., due to bile reflux) → acute pancreatitis — the pancreas digests itself.

Comparison Table

• Pepsinogen → Pepsin: Gastric HCl (in stomach)
• Trypsinogen → Trypsin: Enterokinase (in duodenum)