Function
Nitrate reductase plays a strong role in the nitrogen cycle. It fixes nitrate to nitrite so it can be more easily converted to nitrogen gas for the atmosphere.
Relevance
Nitrates from agricultural runoff can pollute bodies of water and damage the ecosystem. When nitrate concentration increases in water sources, it leads to algal blooms and eutrophication which can drastically reduce the species diversity of the water source. [1]
Structural highlights
where nitrate is fixed to nitrite.