Enzymatic peptide synthesis in organic solvent with different zeolites as immobilization matrixes

A series of zeolite immobilized alpha-chymotrypsin and thermolysin with mic roporous Y zeolites (HY, NH4Y, NaY) and mesoporous dealuminized DAY zeolite s (HDAY, HNH(4)DAY) as matrixes have been prepared to catalyze peptide bond formation in organic solvents for the first time. The results indicated th at most zeolite immobilized enzymes were active for peptide syntheses in or ganic media, and still had catalytic activity to some extent after being re used five times. According to the results, the immobilization effect of mic roporous Y zeolite was better than that of mesoporous DAY zeolite, suggesti ng that microporous Y zeolite can form more powerful hydrogen bonds with en zyme molecules since there are more hydroxyl groups on the Y zeolite than o n the DAY zeolite. In addition, the influences of some reaction conditions such as reaction time and water content of the solvent on the enzymatic pep tide synthesis were also studied and optimized. For the two kinds of protea ses, NH4Y zeolite did not show its advantages for thermolysin, but was more suitable for or-chymotrypsin as an immobilization matrix. (C) 2000 Elsevie r Science Ltd. All rights reserved.