Synthesis of tripeptide derivative Phac-Met-Asp(OMe)-Phe-NH_2 catalyzed by immobilized enzyme is reported. This tripeptide is a fragment of cholecystokinin C-terminal octapeptide CCK-8. Starting with Phac-Met-OCam, the target tripeptide derivative was successfully synthesized with three immobilized enzymes, a-chymotrypsin/ Celite-545, papain/VA-Epoxy and thermolysin/Celite-545 by three reaction steps in reasonable yields. The choice of appropriate enzymes, solvents and immobilization was studied. By a comparative study of free and immobilized enzymatic synthesis, the results also show some advantages of the use of immobilized enzymes.

Key words: POLYPEPTIDE, POLYPEPTIDE, PROTEASE, SYNTHESIS