MolybdenumPteridinesCoenzymesMetalloproteinsTungstenXanthine DehydrogenaseNitrate ReductasesAldehyde OxidaseNitrate ReductaseSulfite OxidaseSulfurtransferasesPterinsXanthine OxidaseTungsten CompoundsOxidoreductases Acting on Sulfur Group DonorsNitrogenaseNitrate Reductase (NADH)SulfurAldehyde OxidoreductasesMolybdoferredoxinRhodobacter capsulatusElectron Spin Resonance SpectroscopyIsotopesOxidoreductasesMetal Metabolism, Inborn ErrorsFormate DehydrogenasesIron-Sulfur ProteinsChloratesAzotobacter vinelandiiXanthineSulfite DehydrogenaseAzotobacterOxidation-ReductionDesulfovibrio gigasNitrogen FixationDithioniteOrganometallic CompoundsMetalloexopeptidasesTracheobiontaSulfitesSpectrophotometryEscherichia coliChlorellaTrace ElementsMilkSulfidesNitrobacterFormatesMethanobacteriumNitratesHumic SubstancesCatalysis