1. A kallikrein-like enzyme in plasma of patients with acute pancreatitis was further purified by successive hydroxyapatite/cellulose and Sepharose-4B column chromatography.
2. By these procedures 0.26 mg of purified enzyme with a specific activity of 215 S-2266 chromozyme units/mg of protein was obtained from 10 ml of original plasma.
3. The purified material was homogeneous as ascertained by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had an apparent molecular weight of 31 000 as measured by gel filtration on Sephadex G-200.
4. It was confirmed immunologically that this enzyme was pancreatic kallikrein, which is distinct from plasma kallikrein, and that it could combine with α2-macroglobulin only in the presence of trypsin.