A proteolytic enzyme formed in the intestine by the cleavage of trypsinogen by enterokinase. Trypsinogen enters the intestine as part of the intestinal juice. It is an endopeptidase that hydrolyzes peptides of arginine or lysine.
- t. fecal tests — see fecal trypsin.
- feline t.-like immunoreactivity (fTLI) — see trypsin-like immunoreactivity (below).
- t. inhibitor — small protein synthesized in the exocrine pancreas which prevents conversion of trypsinogen to trypsin, so protecting itself against trypsin digestion. Pancreatic trypsin inhibitor competitively binds to the active site of trypsin and inactivates it at a very low concentration. The binding is amongst the strongest noncovalent associations, but only a fraction of the potential trypsin is so inhibited.
- t.-like immunoreactivity (TLI) — serum proteins, particularly trypsinogen, react immunologically as trypsin and a normal level is dependent upon a normally functional pancreas. This is used in the diagnosis of exocrine pancreatic insufficiency.
