Incorporation of [18O]water into 4-hydroxybenzoic acid in the reaction of 4-chlorobenzoate dehalogenase from pseudomonas spec. CBS 3.

4-Chlorobenzoate is dehalogenated by 4-chlorobenzoate dehalogenase from Pseudomonas spec. CBS 3 to form 4-hydroxybenzoate. In 18O enriched water the hydroxygroup of 4-hydroxybenzoate is quantitatively labelled with 18O. This result clearly shows, that 4-chlorobenzoate dehalogenase catalyzes the hydrolytic cleavage of the halogen-carbon bond, without the involvement of molecular oxygen, a reaction not yet described.