Enzymatic characterization of a recombinant carbonyl reductase from Acetobacter sp. CCTCC M209061

摘要

Background: Acetobacter sp. CCTCC M209061 could catalyze carbonyl compounds to chiral alcohols following anti-Prelog rule with excellent enantioselectivity. Therefore, the enzymatic characterization of carbonyl reductase (CR) from Acetobacter sp. CCTCC M209061 needs to be investigated. Results: A CR from Acetobacter sp. CCTCC M209061 (AcCR) was cloned and expressed in E. coli. AcCR was purified and characterized, finding that AcCR as a dual coenzyme-dependent short-chain dehydrogenase/reductase (SDR) was more preferred to NADH for biocatalytic reactions. The AcCR was activated and stable when the temperature was under 35℃ and the pH range was from 6.0 to 8.0 for the reduction of 4'-chloroacetophenone with NADH as coenzyme, and the optimal temperature and pH were 45℃ and 8.5, respectively, for the oxidation reaction of isopropanol with NAD~+. The enzyme showed moderate thermostability with half-lives of 25.75 h at 35℃ and 13.93 h at 45℃, respectively. Moreover, the AcCR has broad substrate specificity to a range of ketones and ketoesters, and could catalyze to produce chiral alcohol with e.e. 99% for the majority of tested substrates following the anti-Prelog rule. Conclusions: The recombinant AcCR exhibited excellent enantioselectivity, broad substrate spectrum, and highly stereoselective anti-Prelog reduction of prochiral ketones. These results suggest that AcCR is a powerful catalyst for the production of anti-Prelog alcohols.