재사용이 가능한 효소나노촉매의 개발

Abstract

Dynamic kinetic resolution (DKR) is a great method to make single enantiomeric products from racemic substrates. DKR for (S)-products from alcohols is difficult to achieve because enzymes that make (S)-products are poorly active and unstable. Many researches have been done to solve the problem, but there are still some demerits to overcome

large volume of additives, no recycle of catalyst, etc. In this work, I made magnetically recyclable enzyme nanocatalysts by mechanically mixing iron oxide nanoparticle and Subtilisin.First, I compared the activity of enzyme nanocatalysts with that of native subtilisin in the transesterification of N-Acetyl-L-phenylalanine ethylester (APEE). Vmax of enzyme nanocatalysts is 480 times higher than that of native enzyme and Km of enzyme nanocatalysts is one-fifth to that of native enzyme. Therefore, the catalytic efficiency (Vmax/Km) of enzyme nanocatalysts is 2456 times higher than that of native subtilisin.Next, then recycling of enzyme nanocatalysts was tested in the acylation of 1-phenyl ethanol. No decrease of catalytic activity was observed during 5 recycles. The same result was obtained with 1-(4-chlorophenyl)ethanol as substrate.Last, the DKR of 1-phenyl ethanol was performed with enzyme nanocatalysts. The conversion was 90% and the enantiomeric excess of product was 88%. In addition, the DKR was also possible with the recycling of enzyme nanocatalysts.