Xanthine oxidoreductase (XOR) (XOR)

Xanthine oxidoreductase (XOR) is a complex molybdenum-containing enzyme that serves as the rate-limiting step in the final stages of purine catabolism, specifically the oxidation of hypoxanthine to xanthine and xanthine to uric acid [UniProt P47989]. The enzyme exists in two interconvertible forms: xanthine dehydrogenase (XDH), which utilizes NAD+ as an electron acceptor, and xanthine oxidase (XO), which uses molecular oxygen and generates reactive oxygen species (ROS) such as superoxide and hydrogen peroxide [PubMed: 18410120]. The conversion from XDH to XO is a critical pathological event often triggered by ischemia, inflammation, or proteolysis, leading to significant oxidative stress and tissue injury [PubMed: 24563247]. Clinically, XOR is the primary therapeutic target for the management of hyperuricemia and gout, as its inhibition reduces the systemic production of uric acid [StatPearls: Gout]. Drugs such as allopurinol and febuxostat are widely prescribed to inhibit XOR activity, thereby preventing the deposition of monosodium urate crystals in joints and tissues [PubMed: 30101544]. Beyond gout, XOR is increasingly recognized for its role in cardiovascular and renal diseases due to its contribution to endothelial dysfunction and oxidative damage [PubMed: 26136122].

Other names

Xanthine dehydrogenaseXanthine oxidaseXDHXOXanthine dehydrogenase/oxidase

Xanthine oxidase inhibition