Chloride peroxidase
Chloride peroxidase (EC 1.11.1.10) is a family of enzymes that catalyzes the chlorination of organic compounds. This enzyme combines the inorganic substrates chloride and hydrogen peroxide to produce the equivalent of Cl+, which replaces a proton in hydrocarbon substrate: R-H + Cl− + H2O2 + H+ → R-Cl + 2 H2O In fact the source of "Cl+" is hypochlorous acid (HOCl).