title: Chlorine kinetic isotope effects on the haloalkane dehalogenase reaction.
abstract: We have found chlorine kinetic isotope effects on the dehalogenation catalyzed by haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 to be 1.0045 +/- 0.0004 for 1,2-dichloroethane and 1.0066 +/- 0.0004 for 1-chlorobutane. The latter isotope effect approaches the intrinsic chlorine kinetic isotope effect for the dehalogenation step. The intrinsic isotope effect has been modeled using semiempirical and DFT theory levels using the ONIOM QM/QM scheme. Our results indicate that the dehalogenation step is reversible; the overall irreversibility of the enzyme-catalyzed reaction is brought about by a step following the dehalogenation.
authors.affiliation: Department of Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Lewandowicz
authors.forename: J
authors.initials: J
authors.lastname: Rudziński
authors.forename: L
authors.initials: L
authors.lastname: Tronstad
authors.forename: M
authors.initials: M
authors.lastname: Widersten
authors.forename: P
authors.initials: P
authors.lastname: Ryberg
authors.forename: O
authors.initials: O
authors.lastname: Matsson
authors.forename: P
authors.initials: P
authors.lastname: Paneth
mesh_terms: D000465:Algorithms; D002073:Butanes / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D005025:Ethylene Dichlorides / Q000737:chemistry; D006867:Hydrolases / Q000737:chemistry*; D007554:Isotopes; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D020584:Xanthobacter / Q000201:enzymology
chemical_list: D002073:Butanes; D005025:Ethylene Dichlorides; D007554:Isotopes; D002713:Chlorine; C024565:ethylene dichloride; D006867:Hydrolases; C046137:haloalkane dehalogenase; C006854:butyl chloride