Trypsin

Trypsin is an endopeptidase secreted by the pancreas to aid in the digestion of foods. Because trypsin is highly proteolytic, the pancreas secretes an inactive form of this enzyme (trypsinogen) into the small intestine, where enterokinase cleaves the N-terminal hexapeptide and activates the enzyme. Trypsin specifically cleaves peptide linkages at the carboxyl group of either lysine or arginine, and its optimal pH for activity is between pH 8-9. Trypsin is most effective on partially digested proteins. It also digests some proteins, such as protamines and histones, that cannot be digested by pepsin. The products of trypsin digestion are amino acids and various polypeptides.

A rare, hereditary trypsinogen deficiency has been reported and results in the significant impairment of protein digestion. Symptoms include severe growth inhibition, hypoproteinemia, edema, and diarrhea. Evaluation of pancreatic enzymes in such cases reveals a complete absence of trypsinogen. In addition, increased serum levels of trypsin are found in individuals with cystic fibrosis.