REVERSE HYDROLYSIS REACTION IN AQUEOUS-MEDIUM WITHOUT ANY COSOLVENT -APPLICATION TO SYNTHESIS OF GLYCOSIDIC ESTERS OF TYROSINE

The synthesis of L-tyrosine fructosyl ester, from fructose and L-tyros ine methyl ester, was carried out by a transesterification reaction ca talyzed by alpha-chymotrypsin in water without cosolvent. The effect o f fructose concentration and temperature for the transesterification r eaction were determined on both specific activities and product yield. The influence of the presence of fructose has been studied regarding alpha-chymotrypsin and L-tyrosine fructosyl ester stabilities. It appe ared that an increase of temperature enhanced enzyme activity but slum ped the product yield because of the very weak stability of tyrosine f ructosyl ester.