Bromoperoxidase
Encyclopedia
Bromoperoxidases are enzymes that catalyse the bromination of hydrocarbons. The enzymes accomplish this reaction via the following reaction:
Related chloroperoxidase enzymes effect chlorination.
In the nomenclature of haloperoxidase
, bromoperoxidases classically are unable to oxidize chloride at all. For example, eosinophil peroxidase
appears to prefer bromide over chloride, yet is not considered a bromoperoxidase.
The bromoperoxidase enzymes belongs to the family of oxidoreductase
s, specifically those acting on a peroxide as acceptor peroxidases and haloperoxidase
.
The bromoperoxidases found in marine algae feature vanadium
at the active site (see vanadium bromoperoxidase
). Otherwise vanadium is unusual cofactor in biology. By virtue of this family of enzymes, a variety of brominated natural products have been isolated from marine sources.
Murex
snails have a bromoperoxidase used to produce Tyrian purple
dye. The enzyme is very specific to bromide and physically stable, but has not been characterized as to its active site metal.
The ornate worm, Amphitrite ornata
, is often found in marine environments also inhabited by other Polychaete
worms which produce and contaminate sediments with bromophenols
and bromopyrroles
. These organic halogen metabolites are toxic and it has been found that A. ornata produces a novel debromoperoxidase that detoxifies haloaromatic compounds. The gene
s responsible have been identified.
- RH + Br- + 1/2 H2O2 → RBr + H2O
Related chloroperoxidase enzymes effect chlorination.
In the nomenclature of haloperoxidase
Haloperoxidase
Haloperoxidases are peroxidases that are able to mediate the oxidation of halides by hydrogen peroxide. Both halides and hydrogen peroxide are widely available in the environment....
, bromoperoxidases classically are unable to oxidize chloride at all. For example, eosinophil peroxidase
Eosinophil peroxidase
Eosinophil peroxidase is a haloperoxidase enzyme that in humans is encoded by the EPX gene. The enzyme is a heterodimeric 71-77 kD peroxidase consisting of a heavier glycosylated chain and a lighter nonglycosylated chain...
appears to prefer bromide over chloride, yet is not considered a bromoperoxidase.
The bromoperoxidase enzymes belongs to the family of oxidoreductase
Oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule to another...
s, specifically those acting on a peroxide as acceptor peroxidases and haloperoxidase
Haloperoxidase
Haloperoxidases are peroxidases that are able to mediate the oxidation of halides by hydrogen peroxide. Both halides and hydrogen peroxide are widely available in the environment....
.
The bromoperoxidases found in marine algae feature vanadium
Vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
at the active site (see vanadium bromoperoxidase
Vanadium bromoperoxidase
Vanadium bromoperoxidase is a haloperoxidase, used to synthesize halogenated organic compounds associated with defense and pigmentation in seaweeds and marine algae. It is the source of the bulk of organobromine compounds in the ocean...
). Otherwise vanadium is unusual cofactor in biology. By virtue of this family of enzymes, a variety of brominated natural products have been isolated from marine sources.
Murex
Murex
Murex is a genus of medium to large sized predatory tropical sea snails. These are carnivorous marine gastropod molluscs in the family Muricidae, commonly calle "murexes" or "rock snails"...
snails have a bromoperoxidase used to produce Tyrian purple
Tyrian purple
Tyrian purple , also known as royal purple, imperial purple or imperial dye, is a purple-red natural dye, which is extracted from sea snails, and which was possibly first produced by the ancient Phoenicians...
dye. The enzyme is very specific to bromide and physically stable, but has not been characterized as to its active site metal.
The ornate worm, Amphitrite ornata
Amphitrite ornata
Amphitrite ornata or ornate worm, is a species of marine polycheate worm in the family Terebellidae.Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment may bear setae and parapodia . Some species live freely, either swimming, crawling or burrowing,...
, is often found in marine environments also inhabited by other Polychaete
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worms which produce and contaminate sediments with bromophenols
Organobromine compound
Organobromine compounds are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application is the use of polybrominated diphenyl ethers as fire-retardants. A variety of minor organobromine compounds are found in...
and bromopyrroles
Organobromine compound
Organobromine compounds are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application is the use of polybrominated diphenyl ethers as fire-retardants. A variety of minor organobromine compounds are found in...
. These organic halogen metabolites are toxic and it has been found that A. ornata produces a novel debromoperoxidase that detoxifies haloaromatic compounds. The gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s responsible have been identified.