Multiple choice Nitogenase having 6 unit 7 unit 10 unit 9unit Reveal answer Fill a bubble to check yourself A Correct answer Explanation The nitrogenase enzyme complex is composed of two proteins: the Fe protein (a homodimer with 2 subunits) and the MoFe protein (a heterotetramer with 4 subunits). Together, they form a functional complex consisting of 6 subunits.