2-Haloacid dehalogenase from a 4-chlorobenzoate-degrading Pseudomonas spec. CBS 3

Pseudomonas spec. CBS 3 contains a 2-haloacid dehalogenase induced by chloroacetate. The enzyme was purified about 25-fold to electrophoretic homogeneity by ammonium sulfate fractionation, hydroxyapatite, DEAE-cellulose and gel filtration. The relative molecular masses, as determined by Sephadex G-75 gel filtration and dodecyl sulfate polyacrylamide gel electrophoresis, were 41 000 and 28 000, respectively. The enzyme dehalogenated all monohaloacetates except fluoroacetate. Low activities were found against dichloroacetate and 2,2-dichloropropionate. The enzyme was inactive against trichloroacetate and 3-chloropropionate, it catalysed the stereospecific dehalogenation of L-2-chloropropionate to D-lactate, the rate of dehalogenation being about 20% of the rate of chloroacetate dechlorination. The enzyme activity was not affected by chelating agents and thiol reagents.