High isolated yields in thermolysin-catalysed synthesis of Z-L-aspartyl-L-phenylalanine methyl ester in toluene at controlled water activity

Z-L-Aspartyl-L-phenylalanine methyl and ethyl esters were synthesised enzymatically in toluene by means of the zinc protease thermolysin adsorbed onto Celite R-640(R), which is a porous support able to control the hydration of the protein. The conversion of the two derivatised amino acids into the desired products was complete, leading to >90% isolated yields. Moreover, working with equimolar concentrations of the reactants no purification steps were required. Thermolysin adsorbed onto Celite R-640(R) is shown to he a practical tool to synthesise biologically active peptides in organic media. (C) 2001 Elsevier Science Ltd. All rights reserved.