Enzymatic transesterifications of carbonates in water-restricted environments.

摘要: We investigated the ability of several hydrolases to catalyze reactions with an abiotic water-insoluble substrate, carbonic acid diphenyl ester, also known as carbonate (DPC). In single-phase water/organic systems, turnover numbers (TN) greater than 2 × 104 min−1have been achieved for hydrolysis DPC. The Km values hydrolytic reaction were measured be 200μM and 330μM Candida cylindracea lipase Porcine liver esterase, respectively. addition hydrolysis, we observed transesterification carbonates a wide variety alcohol phenol species. Transesterifications DPC bifunctional alcohols resulted in synthesis polycarbonates. stability activity these enzymes water-restricted environments limit competing reactions. find that, removal water, is reduced more four orders magnitude while diminished only 10-fold (turnover 600 min−1 water-miscible systems 60 pure lipase). Stability (half-life longer 3 days) much single phase (5 h 20% methanol). addition, displayed enantiomeric selectivity transesterifications racemic 2-butanol (greater 80% ee).