"Tryptic-like" activity in sera of patients with pancreatitis.

Serum trypsin esterolytic activity was measured in 106 sera from 61 controls and 45 patients with pancreatitis. A trypsin specific synthetic substrate, N-alpha-benzoyl-L-arginine-paranitroanilide, was used. High levels of enzymatically active trypsin were shown to be present in serum of patients with pancreatitis. No difference between the two samples was noticed for the serum concentrations of alpha-1-antitrypsin and alpha-2-macroglobulin (the two main serum trypsin inhibitors). Active trypsin was contained in the high molecular weight fraction of plasma proteins, corresponding to a complex with alpha-2-macroglobulin. The determination of serum typsin activity as a sensitive test for detection of pancreatitis was demonstrated to be statistically significant.