PEPTIDE-SYNTHESIS CATALYZED BY MODIFIED ALPHA-CHYMOTRYPSIN IN LOW-WATER ORGANIC MEDIA

Enzyme-catalyzed synthesis of peptide bonds in organic solvents has been investigated by using alpha-chymotrypsin either modified with poly(ethylene glycol) or immobilized on different supports, in order to find out the importance of water content in the reaction. High yields of peptide synthesis were obtained whatever the type of enzyme derivative used. By varying the type of support, a modification in the enzyme environment was observed and resulted in a significant increase in the reaction yield when nucleophiles with poor affinity for the enzyme were used. Since organic solvents also affected substrate specificity with respect to the donor ester, a general methodology was proposed for the enzymatic synthesis of peptides in low-water organic media.