Halogenation by Halogeno Peroxidases

Halogeno peroxidases catalyze the substitution of a substrate hydrogen atom by a halogen atom according to the following equation  

They have many properties in common with normal peroxidases (C 2.4.1) and also contain ferriprotoporphyrin IX (D 10.1) as prosthetic group. 

With respect to halogen anions the enzymes possess little substrate specificity. They react with chloride as well as bromide and iodide ions. These halogen anions are probably first oxidized to radicals by means of hydroxyl radicals before substituting the substrate  

Fluoride ions are not used by halogeno peroxidases. This agrees with the fact that HgOg (or OH-radicals) are not capable of oxidizing fluorine. 

Morrison, M., Schonbaum, G. R. Peroxidase-catalyzed halogenation. Annu. Rev. Biochem. 45, 861-888 (1976) 

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