title: Purification and characterization of a bacterial dehalogenase with activity toward halogenated alkanes, alcohols and ethers.
abstract: An enzyme that is capable of hydrolytic conversion of halogenated aliphatic hydrocarbons to their corresponding alcohols was purified from a 1,6-dichlorohexane-degrading bacterium. The dehalogenase was found to be a monomeric protein of relative molecular mass 28,000. The affinity for its substrates was relatively low with Km values for short-chain haloalkanes in the range 0.1-0.9 mM. The aliphatic dehalogenase showed a much broader substrate range than has been reported for halidohydrolases so far. Novel classes of substrates include dihalomethanes, C5-C9 1-halo-n-alkanes, secondary alkylhalides, halogenated alcohols and chlorinated ethers. Several of these compounds are important environmental pollutants, e.g. methylbromide, dibromomethane, 1,2-dibromoethane, 1,3-dichloropropene, and bis(2-chloroethyl)ether. The degradation of chiral 2-bromoalkanes appeared to proceed without stereochemical preference. Optically active 2-bromobutane was converted with inversion of configuration at the chiral carbon atom, suggesting that the dehalogenase reaction proceeds by a nucleophilic substitution involving a carboxyl group or base catalysis.
authors.affiliation: Department of Biochemistry, University of Groningen, The Netherlands.
authors.forename: D B
authors.initials: DB
authors.lastname: Janssen
authors.forename: J
authors.initials: J
authors.lastname: Gerritse
authors.forename: J
authors.initials: J
authors.lastname: Brackman
authors.forename: C
authors.initials: C
authors.lastname: Kalk
authors.forename: D
authors.initials: D
authors.lastname: Jager
authors.forename: B
authors.initials: B
authors.lastname: Witholt
mesh_terms: D000192:Actinomycetales / Q000201:enzymology*; D000438:Alcohols / Q000378:metabolism; D000473:Alkanes / Q000378:metabolism; D004987:Ethers / Q000378:metabolism; D006846:Hydrocarbons, Halogenated / Q000378:metabolism*; D006867:Hydrolases / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000438:Alcohols; D000473:Alkanes; D004987:Ethers; D006846:Hydrocarbons, Halogenated; D006867:Hydrolases; C046137:haloalkane dehalogenase