Multiple choice Nitrogenase enzyme has 4 and 2 subunit 3 and 5 subunit Only 4 subuniit 2 and 5 subunit Reveal answer Fill a bubble to check yourself A Correct answer Explanation The nitrogenase enzyme complex consists of two proteins: the Fe protein, which is a homodimer (2 subunits), and the MoFe protein, which is a heterotetramer (4 subunits). Together, they form the active complex with 4 and 2 subunits.