Nitrate reductase is a key enzyme involved in the first step of nitrate assimilation in plants, fungi and bacteria. H2O + NAD(+) + nitrite = H(+) + NADH + nitrate Binds 1 FAD per subunit. Binds 1 heme group per subunit. Binds 1 Mo-molybdopterin (Mo-MPT) cofactor per subunit. Homodimer. Belongs to the nitrate reductase family.