Hydrogen-uptake Hydrogenase Activity in Nitrogen-fixing AzospiriHum brasilense
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Date
1982
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Abstract
N2-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.