the examination of the biochemical phenotypes of the nif genes suggests that nifc may be concerned with the synthesis or activation of the iron molybdenum cofactor nitrogenase , nifh , besides coding for the structure of nitrogen reductase may also exert a function on the synthesis of nitrogenase , and nifj presumably is required to turn on the expression of nifk ( d ) , nifh or niff .
C0030016
reductase
C0028174
nitrogenase