Phosphatase activity of non-heme chloroperoxidase from the bacterium Serratia marcescens

Haloperoxidases are enzymes capable of formation of carbon-halogen bonds in the presence of hydrogen peroxide and halide ions. A mechanism of halogenation catalyzed by heme- and metal-independent bacterial haloperoxidases differs from other representatives of this group of enzymes. Here we report for the first time that bacterial non-heme haloperoxidases possess a phosphatase activity. Chloroperoxidase from Serratia marcescens W 250 purified up to homogeneity is shown to catalyze p-nitrophenylphosphate hydrolysis (K(m) value, 1.8+/-0.1 mM at pH 5.7). The reaction is activated by Mg(2+) and F(-), and is inhibited by WO(4)(2-), tartrate, acetate and phosphate anions. The irreversible inhibition by phenylmethanesulfonyl fluoride, modifier of serine residue in active site, decreases in the presence of phosphate ions. A mechanism of phosphoesters hydrolysis by non-heme haloperoxidases is proposed.