1887

Abstract

Summary: was grown in ammonia-free glucose/mineral salts media in chemostat culture under oxygen or nitrogen limitation. Selected enzymes of the tricarboxylic acid cycle and poly-β-hydroxybutyrate metabolism were monitored in relation to oxygen supply for both steady and transition states. Two dissolved oxygen concentrations were used for the nitrogen-limited steady state to investigate the possible effects of respiratory protection of nitrogenase on these enzymes. The levels of NADH oxidase, isocitrate dehydrogenase and 2-oxoglutarate dehydrogenase increased markedly on relaxation of oxygen limitation while pyruvate dehydrogenase and citrate synthase were relatively unaffected. β-Ketothiolase and acetoacetyl-CoA reductase levels decreased as oxygen limitation was relaxed. Respiratory activity, as measured by the value, increased with oxygen supply rate. Imposition of oxygen limitation on a nitrogen-limited culture caused an immediate increase in the NADH/NAD ratio but this rapidly readjusted to its previous steady-state value. These changes are discussed in relation to respiratory protection of nitrogenase and poly-β-hydroxybutyrate metabolism in .

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/content/journal/micro/10.1099/00221287-97-2-303
1976-12-01
2019-10-23
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-97-2-303
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