Antiproteolytic activity of goose pancreas: purification, inhibitory properties and amino-acid sequence of a Kazal type trypsin inhibitor.

A trypsin inhibitor of Kazal type has been isolated from goose pancreas by affinity chromatography on immobilized anhydrotrypsin, anion exchange and reverse phase HPLC. It inhibits bovine beta-trypsin with the association constant (Ka) of 5.99 x 10(8) M-1. The complete amino-acid sequence was determined following CNBr treatment. The protein comprised a total of 69 amino-acid residues, corresponding to a molecular mass of 7.7 kDa. The P1-P'1 reactive site bond of the inhibitor was localized at position Lys25-Met26. The amino-acid sequence of GPTI shows extremely high homology to that of other inhibitors isolated from pancreas of birds.