A NOVEL GENERATION OF OPTICALLY-ACTIVE 1,2-DIOLS FROM THE RACEMATES BY USING HALOHYDRIN DEHYDRO-DEHALOGENASE

A novel enzyme dehalogenating halohydrins, designated as halohydrin de hydo-dehalogenase (HDDase), was purified From Alcaligenes sp. DS-S-7G. The enzyme catalyzed oxidative dehalogenation of (R)-3-chloro-1,2-pro panediol [monochlorohydrin (MCH)] to acetic acid and formaldehyde via hydroxyacetone stereoselectively by the addition of artificial electro n accepters. The dehalogenating activity was much higher in the presen ce of 2,6-dichlorophenolindophenol (DCIP) and phenazine methosulfate ( PMS). The resulting stereoselective dehydro-dehalogenation was applica ble to preparation of various optically active halohydrins and 1,2-dio ls so that the respective residual isomers had excellent enantiomeric excesses (ee) (60-99% ee).