Directed Evolution Strategies for Enantiocomplementary Haloalkane Dehalogenases: From Chemical Waste to Enantiopure Building Blocks
作者:Jan G. E. van Leeuwen、Hein J. Wijma、Robert J. Floor、Jan-Metske van der Laan、Dick B. Janssen
DOI:10.1002/cbic.201100579
日期:2012.1.2
Waste not, want not: A carefully optimized directedevolutionstrategy was used to obtain two enantiocomplementaryhaloalkanedehalogenase variants that convert the toxic waste compound 1,2,3‐trichloropropane into either (R)‐ or (S)‐2,3‐dichloropropan‐1‐ol. The products can be converted into optically active epichlorohydrins that could be used for the preparation of various chiral pharmaceuticals.
Haloalkane dehalogenase catalysed desymmetrisation and tandem kinetic resolution for the preparation of chiral haloalcohols
作者:Alja Westerbeek、Jan G.E. van Leeuwen、Wiktor Szymański、Ben L. Feringa、Dick B. Janssen
DOI:10.1016/j.tet.2012.06.059
日期:2012.9
Six different bacterial haloalkane dehalogenases were recombinantly produced in Escherichia coli, purified, and used to catalyse the conversion of prochiral short-chain dihaloalkanes and a meso dihaloalkane, yielding enantioenriched haloalcohols. A two-reaction one-enzyme process was established in which the desymmetrisation of a dihaloalkane is followed by kinetic resolution of the chiral haloalcohol that is produced in the first step. In case of 1,3-dibromo-2-methylpropane and 1,3-dibromo-2-phenylpropane, an increase of the enantiomeric excess of the respective haloalcohol was observed in time, leading to ee values of >97%, with analytical yields of 24 and 52%, respectively. The results show that haloalkane dehalogenases can be used for the production of highly enantioenriched haloalcohols and that in some cases product enantiopurity can be improved by allowing a two-step one-enzyme tandem reaction. (C) 2012 Elsevier Ltd. All rights reserved.
A novel generation of optically active 1,2-diols from the racemates by using halohydrin dehydro-dehalogenase
作者:Toshio Suzuki、Naoya Kasai、Noshi Minamiura
DOI:10.1016/s0957-4166(00)86179-0
日期:1994.1
A novel enzyme dehalogenating halohydrins, designated as halohydrin dehydo-dehalogenase (HDDase), was purified From Alcaligenes sp. DS-S-7G. The enzyme catalyzed oxidative dehalogenation of (R)-3-chloro-1,2-propanediol [monochlorohydrin (MCH)] to acetic acid and formaldehyde via hydroxyacetone stereoselectively by the addition of artificial electron accepters. The dehalogenating activity was much higher in the presence of 2,6-dichlorophenolindophenol (DCIP) and phenazine methosulfate (PMS). The resulting stereoselective dehydro-dehalogenation was applicable to preparation of various optically active halohydrins and 1,2-diols so that the respective residual isomers had excellent enantiomeric excesses (ee) (60-99% ee).