NITROGEN FIXATION: HYDROSULFITE AS ELECTRON DONOR WITH CELL-FREE PREPARATIONS OF AZOTOBACTER VINELANDII AND RHODOSPIRILLUM RUBRUM

Abstract
Hydrosulfite as the electron donor for N2 reduction by cell-free preparations of A. vinelandii was demonstrated and optimal conditions for the reaction determined. Ammonia was the principal product of N2 reduction by the cell-free system. An adenosine triphosphate (ATP)-dependent hydrogenase in the preparations and its inhibition by N2 was demonstrated. Cell-free fixation with extracts of R. rubrum was demonstrated using hydrosulfite as the electron donor and an ATP-generating system.