In order to excavate microbial epoxide hydrolases (EHs) with desired catalytic properties, a novel EH, SfEH1, was identified based on the genome annotation of Streptomyces fradiae and sequence alignment analysis with local protein library. The SfEH1-encoding gene, sfeh1, was then cloned and over-expressed in soluble form in Escherichia coli/BL21(DE3). The optimal temperature and pH of recombinant SfEH1 (reSfEH1) and reSfEH1-expressing E. coli (E. coli/sfeh1) were both determined as 30 ℃ and 7.0, also indicating that the influences of temperature and pH on reSfEH1′s activities were more obvious than those of E. coli/sfeh1 whole cells. Subsequently, using E. coli/sfeh1 as catalyst, its catalytic properties towards thirteen common mono-substituted epoxides were tested, in which E. coli/sfeh1 had the highest activity of 28.5 U/g dry cells for rac-1,2-epoxyoctane (rac-6a), and (R)-1,2-pentanediol ((R)-3b) (or (R)-1,2-hexanediol ((R)-4b)) with up to 92.5% (or 94.1%) ee_p was obtained at almost 100% conversion ratio. Regioselectivity coefficients (α_S and β_R) displayed in the enantioconvergent hydrolysis of rac-3a (or rac-4a) were calculated to be 98.7% and 93.8% (or 95.2% and 98.9%). Finally, the reason of the high and complementary regioselectivity was confirmed by both kinetic parameter analysis and molecular docking simulations.

为了挖掘具有所需催化特性的微生物环氧化物水解酶 (EH)，基于Streptomyces fradiae的基因组注释和与本地蛋白质库的序列比对分析，鉴定了一种新的 EH， Sf EH1。然后克隆Sf EH1 编码基因sfeh 1，并在大肠杆菌/BL21(DE3)中以可溶形式过表达。重组Sf EH1（re Sf EH1）和表达re Sf EH1的大肠杆菌（E. coli / sfeh1)均测定为30℃和7.0，也说明温度和pH值对re Sf EH1活性的影响比大肠杆菌/ sfeh 1全细胞更明显。随后，以大肠杆菌/ sfeh 1为催化剂，测试了其对13种常见单取代环氧化物的催化性能，其中大肠杆菌/ sfeh 1对rac -1,2的活性最高，为28.5 U/g干细胞-环氧辛烷 ( rac - 6a )，和 ( R )-1,2-戊二醇 (( R ) -3b )（或 ( R )-1,2-己二醇 ((R )- 4b )) 以几乎 100% 的转化率获得了ee _{p高达 92.5%（或 94.1%）。}经计算， rac - 3a（或rac - 4a ）的对映聚合水解显示的区域选择性系数（α _S和 β _R ）分别为 98.7% 和 93.8%（或 95.2% 和 98.9%）。最后，动力学参数分析和分子对接模拟证实了高互补区域选择性的原因。