Nitrous-oxide reductase (N2OR)

Nitrous-oxide reductase (N2OR) is a **bacterial metalloenzyme** that catalyzes the final step of denitrification, reducing the potent greenhouse gas **nitrous oxide (N₂O) to inert dinitrogen (N₂)**[1][2][3][4][5]. It is a homodimeric multicopper oxidoreductase located in the periplasm of denitrifying bacteria, with each monomer containing two specialized copper centers: **CuA** (electron transfer site) and **CuZ** (catalytic site; a distinct tetranuclear copper-sulfide cluster)[2][4][5]. Head-to-tail dimerization positions these centers from opposing monomers in optimal proximity for cooperative catalysis[2][4][5]. N2OR is essential for environmental nitrogen cycling and mitigation of greenhouse gas emissions, as it is presently the only known enzyme capable of deleting N₂O from the biosphere[3][4][5]. Its activity is regulated by the *nosZ* gene, and its dysfunction or inhibition (by compounds including acetylene, azide, and cyanide) results in incomplete denitrification and heightened N₂O emissions[1][2][3]. N2OR does not have direct clinical applications or recognized roles in human disease but is a crucial environmental target in efforts to reduce atmospheric N₂O and its associated climate impacts.

Other names

Nitrogen:acceptor oxidoreductase (N₂O-forming)NosZNitrous oxide reductaseN₂O reductase

Inhibitors: Blockage of copper centers and/or active/catalytic sites, preventing electron transfer and subsequent reduction of N₂O to N₂[1]. - Enzymatic catalysis: 2H⁺/2e⁻-dependent reduction of N₂O to N₂ (biotransformation)[2][5].