Substrate specificity of an oxygen dependent sulfoxide synthase in ovothiol biosynthesis.

OvoA is an iron(II) dependent sulfoxide synthase which catalyzes the first step in ovothiol A biosynthesis. This enzyme sulphurizes the C5 position of the imidazole side chain of L-histidine. We report the substrate specificity profile of this catalyst and present data which indicate that OvoA catalysis follows an thiol-ene type mechanism.