Nitrate reductase contains iron and molybdenum.
There are four atoms of Mo and four active sites per enzyme molecule. Cyanide and azide are strong inhibitors. Cyanide inhibition is competitive, but the affinity of the enzyme for cyanide is about 1,000 times that of the affinity for nitrate. Nitrate reductase is used in the measurement of low levels of nitrate. The Size of Nitrate Reductase in Escherichia coli , Biochem.