Bioenergetics of Nitrogenase in Blue-Green Algae. I. Physiological Conditions for Nitrogenase Activity in Phormidium Foveolarum

Abstract

Nitrogenase activity and regulation were examd. in P. foveolarum. Nitrogenase was induced during incubation under Ar atm. after preceding growth with NH4Cl; low light intensity or the presence of DCMU were also required for induction. Nitrogenase activity was dependent on respiratory CO2 evolution. No H-uptake activity was obtained with Phormidium, whereas H and C2H4 evolution catalyzed by nitrogenase were obsd. in cell-free systems using either Nostoc or Phormidium. Different H:C2H4 ratios between the 2 species was explained by the lack of a hydrogenase in Phormidium. [on SciFinder(R)]