Alpha 1-proteinase inhibitor in pure human pancreatic juice. Characterization of a complexed form in patients with chronic calcifying pancreatitis and its significance.

Two forms of alpha 1-proteinase inhibitor (alpha 1-PI) were characterized in the pancreatic juice of patients with chronic pancreatitis, one free form and one form complexed with a proteinase. This complex is probably present in minute amounts in normal pancreatic juice which contains mainly free alpha 1-PI. The proteinase bound to alpha 1-PI has been identified as chymotrypsin A and the inhibitory activity of the free form of alpha 1-PI has been demonstrated. These data underline the rapid conversion of human proteolytic zymogens into active enzymes and demonstrate the increase of this activation phenomenon in the juice of patients with chronic pancreatitis.