Neurospora crassa nit

The molybdenum cofactor was liberated from D. gigas AOR, and under appropriate conditions was transferred quantitatively to nitrate reductase in extracts of Neurospora crassa nit-1 mutant) to yield active nitrate reductase 217). On the basis of molybdenum content, the activity observed for reconstitution with molybdenum cofactor of D. gigas was lower (25%) than the values observed for the procedure using extractable molybdenum cofactor of XO, used as reference. This result can now be put in the context of the difference in pterin present (MPT-XO and MCD-AOR) 218). 

N.r. of Neurospora crassa has M, 228,000. A N.r. mutant (Neurospora crassa nit-3) produces a subunit of N.r. containing cytochrome and Mo (M, 160,000) this does not react with NAD(P)H, but transfers electrons to nitrate from exogenous FADH2 or reduced methyl viologen. The other component is produced by Neurospora crassa nit-I it is unable to reduce nitrate, but catalyses the reduction of cytochrome c by NAD(P)H. 

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