Millar Robert, Rahmanpour Rahman, Yuan Eugenie Wei Jia, White Catharine, Bugg Timothy D H
Department of Chemistry, University of Warwick, Coventry, UK.
Biotechnol Appl Biochem. 2017 Nov;64(6):803-809. doi: 10.1002/bab.1536. Epub 2017 Apr 19.
An extracellular esterase gene estK was identified in Pseudomonas putida mt-2 and overexpressed at high levels in Escherichia coli. The recombinant EstK enzyme was purified and characterized kinetically against p-nitrophenyl ester and other aryl-alkyl ester substrates and found to be selective for hydrolysis of acetyl ester substrates with high activity for p-nitrophenyl acetate (k 5.5 Sec , K 285 µM). Recombinant EstK was found to catalyze deacetylation of acetylated beech xylan, indicating a possible in vivo function for this enzyme, and partial deacetylation of a synthetic polymer (poly(vinylacetate)). EstK was found to catalyze enantioselective hydrolysis of racemic 1-phenylethyl acetate, generating 1R-phenylethanol with an enantiomeric excess of 80.4%.
在恶臭假单胞菌mt-2中鉴定出一种细胞外酯酶基因estK，并在大肠杆菌中高水平过表达。对重组EstK酶进行了纯化，并针对对硝基苯酯和其他芳基烷基酯底物进行了动力学表征，发现其对乙酰酯底物的水解具有选择性，对乙酸对硝基苯酯具有高活性（k = 5.5 s⁻¹，K = 285 μM）。发现重组EstK可催化乙酰化山毛榉木聚糖的脱乙酰化反应，表明该酶可能具有体内功能，还可催化合成聚合物（聚醋酸乙烯酯）的部分脱乙酰化反应。发现EstK可催化外消旋1-苯乙酸乙酯的对映选择性水解，生成对映体过量为80.4%的1R-苯乙醇。
