Molybdenum in Biology - An Essential Trace Element
Essential role of molybdenum
Molybdenum is an essential trace element for several enzymes important to animal and plant metabolism: mammalian xanthine oxidase/xanthine dehydrogenase, aldehyde oxidase, sulfite oxidase, formate dehydrogenase, nitrate reductase and nitrogenase. Molybdenum functions as an electron carrier in those enzymes that catalyse the reduction of nitrogen and nitrate. Molybdenum is essential to plants being necessary for plant production, even though present in plant tissue at a level much lower (0.5 ppm dry matter basis) than the critical levels for other essential elements.
Molybdenum is essential to humans. Molybdenum is needed for at least three enzymes. Sulfite oxidase catalyses the oxidation of sulfite to sulfate, necessary for metabolism of sulfur amino acids. Sulfite oxidase deficiency or absence leads to neurological symptoms and early death. Xanthine oxidase catalyses oxidative hydroxylation of purines and pyridines including conversion of hypoxanthine to xanthine and xanthine to uric acid. Aldehyde oxidase oxidises purines, pyrimidines, pteridines and is involved in nicotinic acid metabolism. Low dietary molybdenum leads to low urinary and serum uric acid concentrations and excessive xanthine excretion.