LARGE ACCELERATION OF ALPHA-CHYMOTRYPSIN-CATALYZED DIPEPTIDE FORMATION BY 18-CROWN-6 IN ORGANIC-SOLVENTS

The effects of 18-crown-6 on the synthesis of peptides catalyzed by al pha-chymotrypsin are reported. Lyophilization of the enzyme in the pre sence of 50 equivalents of 18-crown-6 results in a 425-fold enhanced a ctivity when the reaction between the 2-chloroethylester of N-acetyl-L -phenylalanine and L-phenylalaninamide is carried out in acetonitrile. Addition of crown ether renders the dipeptide synthesis in nonaqueous solvents catalyzed by ci-chymotrypsin possible on a preparative scale . The acceleration is observed in different solvents and for various p eptide precursors. (C) 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59: 553-556, 1998.