What is "nitrite reductase"

n. (context enzyme English) Any enzyme that catalyses the reduction of nitrite ions

Nitrite reductase refers to any of several classes of enzymes that catalyze the reduction of nitrite. There are two classes of NIR's. A multi haem enzyme reduces NO to a variety of products. Copper containing enzymes carry out a single electron transfer to produce nitric oxide.

In enzymology, a nitrite reductase (NO-forming) is an enzyme that catalyzes the chemical reaction

nitric oxide + HO + ferricytochrome c ⇌ nitrite + ferrocytochrome c + 2 H

The 3 substrates of this enzyme are nitric oxide, HO, and ferricytochrome c, whereas its 3 products are nitrite, ferrocytochrome c, and H.

This enzyme belongs to the family of oxidoreductases, specifically those acting on other nitrogenous compounds as donors with a cytochrome as acceptor. The systematic name of this enzyme class is nitric-oxide:ferricytochrome-c oxidoreductase. Other names in common use include cd-cytochrome nitrite reductase, [nitrite reductase (cytochrome)] [misleading, see comments.], cytochrome c-551:O2, NO2+ oxidoreductase, cytochrome cd, cytochrome cd1, hydroxylamine (acceptor) reductase, methyl viologen-nitrite reductase, nitrite reductase (cytochrome, and NO-forming). This enzyme participates in nitrogen metabolism. It has 3 cofactors: FAD, Iron, and Copper.