Trypsinogen-activation peptide (TAP) is a small peptide that is released when trypsinogen is activated to trypsin. Under physiologic conditions, activation of trypsinogen occurs in the intestinal lumen and is catalyzed by enteropeptidase (formerly known as enterokinase). In the intestinal lumen, TAP is quickly degraded by peptidases of the brush border membrane. In pancreatitis, trypsinogen is prematurely activated within pancreatic acinar cells, and TAP is released into the peripheral circulation.

Although TAP is quickly excreted through the kidneys, with a circulating half-life of less than 8 min, significant increases in plasma and urine TAP concentrations have been reported in canine and human patients with acute pancreatitis. Trypsinogen activation peptide (TAP) may be an early marker of severe pancreatitis.