Abstract High enantioselectivities were obtained in chloroperoxidase catalyzed oxidation of organic sulfides (99% ee in the case of methyl 2-pyridyl sulfide) with H 2 O 2 in aqueous buffer solution, pH 5, at 25 C. The kinetic parameters in the oxidation of a series of sulfides both with H 2 O 2 and tert-butyl hydroperoxide were determined and the data are consistent with enzymatic oxidation involving presumably a ternary complex, in all cases the reaction ...