Abstract：
The asymmetric reduction of α, β-unsaturated compounds conjugated with electron-withdrawing group by ene-reductases (ERs) is a valuable method for the synthesis of enantiopure chiral compounds. This study introduced an ER from Corynebacterium casei (CcER) which was heterologously expressed in Escherichia coli BL21(DE3), and the purified recombinant CcER was characterized for its biocatalytic properties. CcER exhibited the highest specific activity at 40 °C and pH 6.5, and showcased appreciable stability below 40 °C over a pH range of 6.0-7.0. The enzyme displayed high resistance to methanol. CcER accepted NADH or NADPH as a cofactor and exhibited a broad substrate spectrum towards α, β-unsaturated compounds. It achieved complete conversion of 2-cyclohexen-1-one and good performance for stereoselective reduction of (R)-carvone (conversion 98 %, diastereoselectivity 96 %). This study highlights the robustness and potential of CcER.
摘要：
α的不对称还原，通过烯还原酶（ER）与吸电子基团缀合的β-不饱和化合物是合成对映纯手性化合物的有价值的方法。这项研究引入了一个来自干酪棒杆菌（CcER）的ER，该ER在大肠杆菌BL21（DE3）中异源表达，并表征了纯化的重组CcER的生物催化性能。CcER在40°C和pH6.5时表现出最高的比活性，并且在40°C以下在6.0-7.0的pH范围内表现出明显的稳定性。该酶表现出对甲醇的高抗性。CcER接受NADH或NADPH作为辅因子，并表现出对α的宽底物谱，β-不饱和化合物。它实现了2-环己烯-1-酮的完全转化和（R）-香芹酮的立体选择性还原的良好性能（转化率98％，非对映选择性96%)。这项研究强调了CcER的稳健性和潜力。
