Xanthine dehydrogenase

Xanthine dehydrogenase, also known as XDH, is a is_associated_with::protein that, in humans, is encoded by the XDH is_associated_with::gene.

Function
Xanthine dehydrogenase belongs to the group of is_associated_with::molybdenum-containing is_associated_with::hydroxylases involved in the oxidative metabolism of is_associated_with::purines. The enzyme is a homodimer. Xanthine dehydrogenase can be converted to is_associated_with::xanthine oxidase by reversible sulfhydryl oxidation or by irreversible proteolytic modification.

Xanthine dehydrogenase catalyzes the following is_associated_with::chemical reaction:



xanthine + NAD+ + H2O $$\rightleftharpoons$$ urate + NADH + H+

The three substrates of this enzyme are is_associated_with::xanthine, NAD+, and H2O, whereas its three products are is_associated_with::urate, NADH, and H+.

This enzyme participates in is_associated_with::purine metabolism.

Nomenclature
This enzyme belongs to the family of is_associated_with::oxidoreductases, to be specific, those acting on CH or CH2 groups with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is xanthine:NAD+ oxidoreductase. Other names in common use include NAD+-xanthine dehydrogenase, xanthine-NAD+ oxidoreductase, xanthine/NAD+ oxidoreductase, and xanthine oxidoreductase.

Clinical significance
Defects in xanthine dehydrogenase cause is_associated_with::xanthinuria, may contribute to adult respiratory stress syndrome, and may potentiate influenza infection through an oxygen metabolite-dependent mechanism.