Bromide peroxidase (, ''bromoperoxidase'', ''haloperoxidase (ambiguous)'', ''

eosinophil peroxidase Eosinophil peroxidase is an enzyme found within the eosinophil granulocytes, innate immune cells of humans and mammals. This oxidoreductase protein is encoded by the gene ''EPX'', expressed within these myeloid cells. EPO shares many similarities ...

'') is a family of

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ...

s with

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ...

''bromide:hydrogen-peroxide oxidoreductase''. These enzymes catalyses the following

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breakin ...

: : HBr + H₂O₂

\rightleftharpoons

HOBr + H₂O The HOBr is a potent brominating agent. The many organobromine compounds observed in marine environments are the products of reaction with this oxidized form of bromine. Bromo peroxidases of red and brown marine algae (''

Rhodophyta Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

'' and '' Phaeophyta'') contain

vanadate In chemistry, a vanadate is an anionic coordination complex of vanadium. Often vanadate refers to oxoanions of vanadium, most of which exist in its highest oxidation state of +5. The complexes and are referred to as hexacyanovanadate(III) and no ...

(

vanadium bromoperoxidase Vanadium bromoperoxidases are a kind of enzymes called haloperoxidases. Its primary function is to remove hydrogen peroxide which is produced during photosynthesis from in or around the cell. By producing hypobromous acid (HOBr) a secondary react ...

). 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. Related chloroperoxidase enzymes effect chlorination. In the nomenclature of

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 Nernst equation shows that hydrogen peroxide can oxidize chlor ...

, bromoperoxidases classically are unable to oxidize chloride at all. For example,

appears to prefer bromide over chloride, yet is not considered a bromoperoxidase because it is able to use chloride.

Muricidae Muricidae is a large and varied taxonomic family of small to large predatory sea snails, marine gastropod mollusks, commonly known as murex snails or rock snails. With about 1,600 living species, the Muricidae represent almost 10% of the Neoga ...

(was ''

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 called "murexes" or "rock snails".Houart, R.; Gofas, S. (2010). Murex Linnaeus, 17 ...

'') spp. snails have a bromoperoxidase used to produce

Tyrian purple Tyrian purple ( grc, πορφύρα ''porphúra''; la, purpura), also known as Phoenician red, Phoenician purple, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It is ...

dye. The enzyme is very specific to bromide and physically stable, but has not been characterized as to its active site metal. , no specific gene has been assigned to such an enzyme in the snail genome. Such an activity is probably provided by symbiotic ''

Bacillus ''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum ''Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacill ...

'' bacteria instead. The identified enzyme belongs to the

alpha/beta hydrolase superfamily The alpha/beta hydrolase superfamily is a superfamily of hydrolytic enzymes of widely differing phylogenetic origin and catalytic function that share a common fold. The core of each enzyme is an alpha/beta-sheet (rather than a barrel), containi ...

; a structure for a similar bromoperoxidase is available as . It runs on a

catalytic triad A catalytic triad is a set of three coordinated amino acids that can be found in the active site of some enzymes. Catalytic triads are most commonly found in hydrolase and transferase enzymes (e.g. proteases, amidases, esterases, acylases, li ...

of Ser 99, Asp 229 and His 258 and does not require metal cofactors.

Additional reading

* * * * *

References

External links

* {{Portal bar, Biology, border=no EC 1.11.1