What is "nitroreductase"

n. (context enzyme English) An enzyme that catalyzes the reduction of nitro groups

Nitroreductases are a family of evolutionarily related proteins involved in the reduction of nitrogen-containing compounds, including those containing the nitro functional group. Members of this family utilise FMN as a cofactor and are often found to be homodimers.

Members of this family include oxygen-insensitive NAD(P)H nitroreductase (FMN-dependent nitroreductase) ( 6,7-dihydropteridine reductase) and NADH dehydrogenase . 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 , D. melanogaster , , 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 E. cloaca 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. The iodotyrosine deiodenase of mammals is a dehalogenase, the BluB of Sinorhizobium meliloti canibalizes the bound FMN to 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.