Nitroreductases are a family of evolutionarily related proteins involved in the reduction of nitrogen-containing compounds, including those containing the

nitro Nitro may refer to: Chemistry *Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed: **Nitro compound, an organic compound containing one or more nitro functional groups, -NO2 **Nitroalkene, ...

functional group. Members of this family utilise

flavin mononucleotide Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin (vitamin B2) by the enzyme riboflavin kinase and functions as the prosthetic group of various oxidoreductases, including NADH dehydrogenase, as ...

as a cofactor and are often found to be homodimers. Members of this family include oxygen-insensitive NAD(P)H nitroreductase (flavin mononucleotide-dependent nitroreductase) (

6,7-dihydropteridine reductase In enzymology, 6,7-dihydropteridine reductase (, also Dihydrobiopterin reductase) is an enzyme that catalyzes the chemical reaction : 5,6,7,8-tetrahydropteridine + NAD(P)+ \rightleftharpoons 6,7-dihydropteridine + NAD(P)H + H+ The four substrat ...

) () and

NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the for ...

(). A number of these proteins are described as oxidoreductases. They are primarily found in bacterial lineages though a number of eukaryotic homologs have been identified: ''

C. elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (r ...

'' , ''

D. melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...

'' , , mouse and human . This protein is not found in photosynthetic eukaryotes. The sequences containing this entry in photosynthetic organisms are possible false positives. The nitroreductase of ''Enterobacter cloacae'' was identified by Bryant and Deluca in a strain isolated from a munitions facility, on the basis of its ability to metabolize TNT (trinitrotoluene). Since then many homologues have been identified and the family is now known to include members in diverse organisms, that catalize diverse reactions. Th
iodotyrosine deiodenase
of mammals is a dehalogenase, th
BluB of ''Sinorhizobium meliloti''
cannibalizes the bound flavin mononucleotideto furnish a critical intermediate in vitamin B12 biosynthesis. Crystal structures of the
E. cloacae
' and
E. coli
' enzymes have been published with a variety of substrates and analogues bound. An example of a potential cold-active enzyme for prodrug therapy was described using a cold-active nitroreductase, Ssap-NtrB (Çelik and Yetis, 2012). Despite Ssap-NtrB derived from a mesophilic bacterium, it showed optimal activity at 20°C against cancer prodrugs. Authors comment that the cold-activity of this novel enzyme will be useful for therapies in combination with crymotherapy, exposing the target tissue to low temperatures in order to trigger the enzyme activity to activate the drug only where is required. Moreover, the enzyme could also be used for

bioremediation Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluent ...

of compounds of explosive and volatile nature in regions where high activity at low temperatures is needed.

Subfamilies

* Cob(II)yrinic acid a,c-diamide reductase

Human proteins containing this domain

IYD Iodotyrosine deiodinase, also known as iodotyrosine dehalogenase 1, is a type of deiodinase enzyme that scavenges iodide by removing it from iodinated tyrosine residues in the thyroid gland. These iodinated tyrosines are produced during thyroid ...

;

References

Protein domains Single-pass transmembrane proteins {{membrane-protein-stub