| Summary: | 碩士 === 輔仁大學 === 食品營養學系 === 93 === A non-steroidal anti-inflammatory-drug, S-ibuprofen was found to have anticancer properties recently, however, the therapeutic S-form enantiomer is unavailable in the market owing to no feasible means of resolution by practical chemical synthesis. Enzymatic-resolution method of pure chiral compounds has been approached nowadays. Escherichia coli thioesterase I, also exhibiting esterase, lysophospholipase and protease activities, is certified to enzymatic enantioselectivity. We have established the synthesis of ibuprofen esters with varied alcohols as well as their identification system by chiral HPLC. E. coli wild type thioesterase I (THWT), the mutant enzyme (L109P) and Candida rugosa lipase (CRL) were employed for the enzymatic resolution of ibuprofen. Ibuprofen acid showed the fastest spontaneous esterification reaction when reacting with methanol, than when reacting with ethanol and isopropanol in n-hexane. It was observed that these spontaneous reactions were inhibited by enzyme addition. THWT showed higher inhibition tendency than did L109P, but no inhibition was observed by CRL. The enzyme catalyzed esterification of ibuprofen acid was not obvious. In the hydrolysis tests of p-nitrophenyl ibuprofen, CRL had better hydrolytic ability than THWT. It was found that the hydrolytic products did not increase in the THWT reaction set after 6 h. It is presumable that ibuprofen bonds thioesterase I to form an irreversible complex structure and that thereby stops the reaction. The e.e. value of CRL resolving ibuprofen enantiomer was up to 58% by 24-h reaction. It might be promising that the development of CRL catalyzing p-nitrophenyl ibuprofen hydrolysis is capable for industrially manufacturing in the future.
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