STABILITY OF NITROGEN-FIXING ENZYMES AND THE REACTIVATION OF A COLD LABILE ENZYME

Abstract

Extracts from Clostridium pasteurianum lose approximately 95% of their activity for N2-fixation during storage under H2 at 00 for 24 hr. Ascorbic-acid, Na2S2O4 and reduced lipoic-acid were useful stabilizing agents. The N2-fixing enzyme complex is cold-labile and retains activity best near 20[degree] when stored under H2. Preparations partially inactivated by storage for 6 hr. at 0[degree] were restored to full activity by incubation under H2 at 22[degree] for an hr., whereas preparations stored for 24 hr. at 0[degree] recovered only 57% of their activity under H2 at 220 for 7 hr. H2 is specifically functional in reactivation, but the basis for inactivation and reactivation of the N2-fixing complex is not apparent.