Acid stable trypsin i~~bit~r in bile

Acid stable trypsin inhibitor having the same antigenicity as urinary trypsin inhibitor was first identified in the bile of patients with rn~i~~t tumors (biliary tract carcinoma or pancreas head carcinoma) and gallstones. Bile trypsin inhibitor from malignant tumor patients was partially purified by DEAE cellulose ion exchange column chromatography. Two molecular forms of the inhibitor were identified. The main form had a molecular weight of about 86000 and the minor one a molecular weight of 31000 as determined by gel filtration. Using isoelectric focussing, the larger molecular form gave a pZ value of 2.0 and the smaller form, a pZ value of 5.1. The isolated larger form migrated on the slightiy cationic side of human serum albumin by analytical poiya~~la~de gel electrophoresis. The larger form reacted and fused with anti-urinary trypsin inhibitor serum and strongly inhibited trypsin, partially inhibited chymotrypsin and plasmin, but did not inhibit urokinase. The clinical significance of acid stable%ypsin inhibitor is discussed.