Chloride peroxidase

Chloride peroxidase (<a href="/facts/Enzyme_Commission_number/Y5GNLRKX">EC</a> <a href="https://enzyme.expasy.org/EC/1.11.1.10">1.11.1.10</a>) is a family of <a href="/facts/Enzyme/DSI1Fh7y">enzymes</a> that catalyzes the <a href="/facts/Chlorination_reaction/vYrGVWcJ">chlorination</a> of organic compounds. This enzyme combines the inorganic substrates <a href="/facts/Chloride/m9NUaUDR">chloride</a> and <a href="/facts/Hydrogen_peroxide/vju6HBIc">hydrogen peroxide</a> 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). Many organochlorine compounds are <a href="/facts/Biosynthesis/aFk7Tk7f">biosynthesized</a> in this way.
This enzyme belongs to the family of <a href="/facts/Oxidoreductase/neW0G5D4">oxidoreductases</a>, specifically those acting on a peroxide as acceptors (peroxidases). The <a href="/facts/List_of_enzymes/w2RP6EwU">systematic name</a> of this enzyme class is chloride:hydrogen-peroxide oxidoreductase. This enzyme is also called chloroperoxidase. It employs one <a href="/facts/Cofactor_(biochemistry)/AGo0PCUU">cofactor</a> which may be either <a href="/facts/Heme/fRhyJAAb">heme</a> or vanadium.
The heme-containing chloroperoxidase (CPO) exhibits peroxidase, <a href="/facts/Catalase/CcJ9r5KG">catalase</a> and <a href="/facts/Cytochrome_P450/alxusFD0">cytochrome P450</a>-like activities in addition to catalyzing halogenation reactions. Despite functional similarities with other heme enzymes, the structure of CPO is unique, which folds into a tertiary structure dominated by eight helical segments. The catalytic acid base, required to cleave the peroxide O-O bond, is glutamic acid rather than histidine as in <a href="/facts/Horseradish_peroxidase/7jxXcwlx">horseradish peroxidase</a>.

Chloride peroxidase open-in-new

Chloride peroxidase