Nitrogenase is unable to discriminate between O2 and N2, and the O2 will degradatively oxidize the FE-S cofactors of the nitrogenase, rendering it more inefficient under increasingly aerobic conditions.

nitrogenase

Nitrogenase contains an FE-S cluster at the active site, and most contain a molybdenum atom centered in the heterometal complex.

by concentrate oxygen using leghemoglobin

Nitrogenase enzyme is used by nitrogen fixing bacteria to split molecules of nitrogen gas and combine the nitrogen atoms with hydrogen.Nitrogenase is the enzyme used by some organisms to fix atmospheric nitrogen gas (N2). It is the only known family of enzymes which accomplishes this process