Yin Jin-Gang, Xu Guo-Chao, Zheng Gao-Wei, Xu Jian-He
Laboratory of Biocatalysis and Synthetic Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Appl Biochem Biotechnol. 2015 Jun;176(4):1102-13. doi: 10.1007/s12010-015-1632-0. Epub 2015 May 1.
A new esterase gene abmbh, encoding a benzoate hydrolase which can enantioselectively hydrolyze l-menthyl benzoate to l-menthol, was recently identified from the genomic library of a soil isolate Acinetobacter sp. ECU2040. The abmbh gene contains a 1080-bp open reading frame encoding a protein of 360 amino acids with a calculated molecular mass of 40.7 kDa. The corresponding enzyme AbMBH was functionally expressed in Escherichia coli BL21 (DE3), purified, and characterized. The AbMBH displayed the maximum activity towards p-nitrophenyl butyrate at 50 °C, and an optimum pH of 8.5. A K M of 2.6 mM and a k cat of 0.26 s(-1) were observed towards dl-menthyl benzoate. The AbMBH exhibited a moderate enantioselectivity (E = 27.5) towards dl-menthyl benzoate. It can also catalyze the enantioselective hydrolysis of a variety of racemic menthyl esters, including dl-menthyl acetate, dl-menthyl chloroacetate, and dl-menthyl butyrate.
最近从土壤分离株不动杆菌属ECU2040的基因组文库中鉴定出一个新的酯酶基因abmbh，其编码一种苯甲酸水解酶，该酶可对映选择性地将苯甲酸l-薄荷酯水解为l-薄荷醇。abmbh基因包含一个1080 bp的开放阅读框，编码一个由360个氨基酸组成的蛋白质，计算分子量为40.7 kDa。相应的酶AbMBH在大肠杆菌BL21(DE3)中实现了功能表达、纯化及特性鉴定。AbMBH在50°C时对丁酸对硝基苯酯表现出最大活性，最适pH为8.5。对dl-薄荷基苯甲酸酯的K M为2.6 mM，k cat为0.26 s(-1)。AbMBH对dl-薄荷基苯甲酸酯表现出中等的对映选择性(E = 27.5)。它还可以催化多种外消旋薄荷酯的对映选择性水解，包括dl-乙酸薄荷酯、dl-氯乙酸薄荷酯和dl-丁酸薄荷酯。
