Purification and characterization of haloalcohol dehalogenase from Arthrobacter sp. strain AD2.
An enzyme capable of dehalogenating vicinal haloalcohols to their corresponding epoxides was purified from the 3-chloro-1,2-propanediol-utilizing bacterium Arthrobacter sp. strain AD2. The inducible haloalcohol dehalogenase converted 1,3-dichloro-2-propanol, 3-chloro-1,2-propanediol, 1-chloro-2-propanol, and their brominated analogs, 2-bromoethanol, as well as chloroacetone and 1,3-dichloroacetone. The enzyme possessed no activity for epichlorohydrin (3-chloro-1,2-epoxypropane) or 2,3-dichloro-1-propanol. The dehalogenase had a broad pH optimum at about 8.5 and a temperature optimum of 50 degrees C. The enzyme followed Michaelis-Menten kinetics, and the Km values for 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol were 8.5 and 48 mM, respectively. Chloroacetic acid was a competitive inhibitor, with a Ki of 0.50 mM. A subunit molecular mass of 29 kDa was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. With gel filtration, a molecular mass of 69 kDa was found, indicating that the native protein is a dimer. The amino acid composition and N-terminal amino acid sequence are given.
van den Wijngaard
A J
AJ
Department of Biochemistry, University of Groningen, The Netherlands.
Reuvekamp
P T
PT
Janssen
D B
DB
D000595:Amino Acid Sequence; D001173:Arthrobacter / Q000201:enzymology*; D015153:Blotting, Western; D002845:Chromatography; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006882:Hydroxyapatites; D007700:Kinetics; D008190:Lyases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity
D006882:Hydroxyapatites; D017886:Durapatite; D008190:Lyases; C066813:haloalcohol hydrogen-halide lyase