Nitrogenase is the enzyme of biological nitrogen fixation. The most wide-spread and most efficient nitrogenase contains a molybdenum cofactor. This protein family, VnfK, represents the beta subunit of the vanadium (V)-containing alternative nitrogenase. It is homologous to NifK and AnfK, of the molybdenum-containing and the iron (Fe)-only types, respectively. [Central intermediary metabolism, Nitrogen fixation]
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