Nitrogenase bioelectrocatalysis: heterogeneous ammonia and hydrogen production by MoFe protein
Journal Article - Open Access
Department of Chemistry, University of Utah Salt Lake City United States
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Nitrogenase is the only enzyme known to catalyze the reduction ofN2 to 2NH3. In vivo, the MoFe protein component of nitrogenase is exclusively reduced by the ATP-hydrolyzing Fe protein in a series of transient associationdissociation steps that are linked to the hydrolysis of two ATP for each electron transferred. We report MoFeprotein immobilized at an electrode surface, where cobaltocene asan electron mediator that can be observed in real time at a carbon electrode is used to reduce the MoFe protein independent of the Fe protein and of ATP hydrolysis and support the bioelectrocatalytic reduction of protons to dihydrogen, azide to ammonia, and nitrite to ammonia. Bulk bioelectro synthetic N3 - or NO2 - reduction 50 mMfor 30 minutes yielded 70 - 9 nmol NH3 and 234 - 62 nmol NH3,with NO2 - reduction operating at high faradaic efficiency.
- Physical Chemistry