During the enzymic reduction of N2 to NH3 by Mo-nitrogenase, free hydrazine (N2H4) is not detectable, but an enzyme-bound intermediate can be made to yield N2H4 by quenching the enzyme during turnover [Thorneley, Eady & Lowe (1978) Nature (London) 272, 557-558]. In contrast, we show here that the V-nitrogenase of Azotobacter chroococcum produces a small but significant amount of free N2H4 (up to 0.5% of the electron flux resulting in N2 reduction) as a product of the reduction of N2. The amount of N2H4 formed increased 15-fold on increasing the assay temperature from 20 degrees C to 40 degrees C. Activity cross-reactions between nitrogenase components of Mo- and V-nitrogenases showed that the formation of free N2H4 was associated with the VFe protein. These data provide the first direct evidence for an enzyme intermediate at the four-electron-reduced level during the reduction of N2 by V-nitrogenase.
Research Article| July 15 1991
Hydrazine is a product of dinitrogen reduction by the vanadium-nitrogenase from Azotobacter chroococcum
M J Dilworth;
Biochem J (1991) 277 (2): 465–468.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
M J Dilworth, R R Eady; Hydrazine is a product of dinitrogen reduction by the vanadium-nitrogenase from Azotobacter chroococcum. Biochem J 15 July 1991; 277 (2): 465–468. doi: https://doi.org/10.1042/bj2770465
Download citation file: