Pedrosa, F.O.Stephan, M.Dobereiner, J.Yates, M.G.2014-07-252014-07-251982http://hdl.handle.net/123456789/4403N2-fixing Azospirillum brasilense possesses an Hruptake hydrogenase activity capable of Importing H,-dependent acetylene reduction by whoie cells starved of carbon metabolites. H2 did not support acetylene reduction in carbon-sufficient bacteria, although carbon subtrates did not inhibit H2-dependent respiration. H,-dependent respiration was extremely O2 sensitive and could not usually protect nitrogenase against inhibition by O2. H2 partly inhibited nitrogenase activity at sub-optimal 0, concentrations: this may be because H2-dependent respiration has a greater affinity for 0, but is less efficiently coupled to ATP production than is carbon-dependent respiration.enArticle