title: Activation of nit-1 nitrate reductase by W-formate dehydrogenase.
abstract: Formate dehydrogenase ( FDH ) from Clostridium thermoaceticum is a known tungsten enzyme. FDH was tested for the presence of nitrogenase-type cofactor and nitrate reductase-type cofactor by the Azotobacter vinelandii UW-45 and Neurospora crassa nit-1 reconstitution assays, respectively. Tungsten formate dehydrogenase (W- FDH ), containing only a small Mo impurity, activated the nit-1 nitrate reductase extracts when molybdate was also added, but not when tungstate was added. These results show W- FDH contains the cofactor common to all known Mo-enzymes except nitrogenase. The difference between the redox chemistries of W- FDH and W-substituted sulfite oxidase appears to relate to differences in tungsten ligation other than that donated by the cofactor or to variations in the protein environment surrounding the tungsten active site.
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D001395:Azotobacter / Q000201:enzymology; D003013:Clostridium / Q000201:enzymology; D004789:Enzyme Activation; D005560:Formate Dehydrogenases / Q000378:metabolism*; D009492:Neurospora crassa / Q000201:enzymology; D009565:Nitrate Reductases / Q000378:metabolism*; D009591:Nitrogenase / Q000378:metabolism
chemical_list: D005560:Formate Dehydrogenases; D009591:Nitrogenase; D000445:Aldehyde Oxidoreductases; D009565:Nitrate Reductases