PHYSICAL AND CHEMICAL ASPECTS OF THE TWO-PHASE SYSTEM ENZYMIC STEP OF A SWEETENER DIPEPTIDE SYNTHESIS

摘要

Several fungal and bacterial proteases, crude or purified enzymes have been immobilized by physical adsorption onto a support (mechanically rigid resin type Amberiite XAD), followed by crosslinking with glutardialdehyde. The enzymatic concentration (expressed by activity reported to ml solution), the optimum pH, time and temperature values for the adsorption, as well as the glutardialdehyde ratio have been studied in order to accomplish immobilization. The results are presented comparatively for different type of proteases tested. From the immobilized enzymes, it was immobilized thermolysin that have been used for the synthesis of a particular N-protected dipeptide ester in organic solvent. The efectiveness of some organic solvents, such as ethyl acetate, 1,2-dichloroethane and chloroforme was tested upon the yield and synthesis rate of the reaction for preparing PhAc-NH-Asp-PheOMe. Synthesis and hydrolysis of PhAc-NH-Asp-PheOMe were studied both in saturated buffer solutions and in aqueous-organic biphasic system.