摘要
由于二芳香基甲酮的位阻大及羰基两侧的取代基差异性较小,对其进行不对称还原是生物催化中具有挑战性的难题之一。文中通过对毕赤酵母GS115基因组序列的分析,发现了一个潜在羰基还原酶基因pascr。将该基因克隆、表达在大肠杆菌Rosetta2(DE3)中,通过Ni-NTA对重组蛋白进行了分离纯化,并对酶的性质进行了研究。PasCR专一性利用NADPH作为辅酶,其最适反应pH为6.5;最适反应温度为35℃;凝胶层析实验结合SDS-PAGE分析表明PasCR在溶液中以二聚体形式存在。PasCR能够不对称还原位阻较大的二芳香基甲酮类化合物,如4-甲基二苯甲酮、4-氯二苯甲酮、2-氯二苯甲酮等,对4-甲基二苯甲酮的还原产物的ee值达到了85%。
Asymmetric reduction of bulky diaryl ketones is still one of the challenging tasks in biocatalysis. By genomic data mining, a putative carbonyl reductase gene pascr was found in Pichia pastoris GS115. pascr was cloned and over-expressed in Escherichia coli Rosseta2 （DE3）. The recombinant enzyme was purified to homogeneity by Ni-NTA column and its catalytic properties were studied. PasCR strictly used NADPH as cofactor, gel filtration and SDS-PAGE analysis suggested that the native form of PasCR was a dimmer. PasCR exhibited the highest activity at 35 ℃ in phosphate buffer at pH 6.5. The enzyme catalyzed the reduction of some bulky diaryl ketones, such as 4-methylbenzophenone, 2-methylbenzophenone and 4-chlorobenzophenone, especially for 4-methylbenzophenone, the product S - alcohol was obtained with 85% ee.
出处
《生物工程学报》
CAS
CSCD
北大核心
2013年第1期68-77,共10页
Chinese Journal of Biotechnology
基金
中国科学院知识创新工程重点方向项目(No.KSCX2-EW-G-14)
国家重点基础研究发展计划(No.2011CB710801)
天津科技计划项目(No.10ZCZDSY06600)资助~~
