Isolation and characterization of a pancreatic elastase from plasma of patients with acute pancreatitis.

1. An elastase-like enzyme in plasma of patients with acute pancreatitis was purified by DEAE-cellulose column chromatography and polyacrylamide-gel disc electrophoresis. 2. In this way 0.24 mg of purified enzyme with a specific activity of 3.94 succinyl-L-alanyl-L-alanyl-L-alanyl-p-nitroanilide units/mg of protein was obtained from 10 ml of plasma. 3. The purified material was homogeneous as ascertained by sodium dodecyl sulphate/polyacrylamide-gel disc electrophoresis and had an apparent molecular weight of 24 000 as measured by gel filtration on Sephadex G-100. 4. This enzyme hydrolysed denatured casein and Congo Red-elastin as well as succinyl-L-alanyl-L-alanyl-L-alanyl-p-nitroanilide. Its amidolytic activity was inhibited by soya bean trypsin inhibitor, but not by aprotinin. 5. Although the enzyme was immunologically similar to elastase 2, its kinetic properties and substrate specificity were apparently different. 6. We propose that an elastase-like enzyme, probably different from elastase 1 or elastase 2, is liberated from the pancreas into blood during acute pancreatitis and becomes combined with alpha 2-macroglobulin.