Purification and properties of fluoroacetate dehalogenase from Pseudomonas fluorescens DSM 8341

The degradation of fluoroacetate by microorganisms has been established for some time, although only a handful of dehalogenases capable of hydrolyzing the stable C-F bond have been studied. Pseudomonas fluorescens DSM 8341 was originally isolated from soil and readily degrades fluoroacetate, thus it was thought that its dehalogenase might have some desirable properties. The enzyme was purified from cell-free extracts and characterised: it is a monomer of 32,500 Da, with a pH optimum of 8 and is stable between pH 4 and 10; its activity is stimulated by some metal ions (Mg(2+), Mn(2+) and Fe(3+)), but inhibited by others (Hg(2+), Ag(2+)). The enzyme is specific for fluoroacetate, and the K(m) for this substrate (0.68 mM) is the lowest determined for enzymes of this type that have been investigated to date.