xantinoksidase

Xanthine oxidase is an enzyme that plays a crucial role in purine metabolism. It is primarily found in the liver and intestinal lining of mammals. This enzyme catalyzes the oxidation of hypoxanthine to xanthine and then further oxidizes xanthine to uric acid. This process is the final step in the breakdown of purines in humans and many other primates.

The activity of xanthine oxidase is important for regulating uric acid levels in the body. In humans, uric acid is the end product of purine metabolism, and while it acts as an antioxidant, excessive levels can lead to conditions like gout, a form of inflammatory arthritis characterized by the deposition of uric acid crystals in joints.

Xanthine oxidase is a metalloflavoprotein, meaning it contains both metal ions, typically molybdenum, and flavin cofactors, specifically flavin adenine dinucleotide (FAD). These cofactors are essential for its catalytic activity. The enzyme exists in two forms: a dehydrogenase form and an oxidase form, with the latter being more prevalent under aerobic conditions.

Inhibition of xanthine oxidase is a therapeutic target for managing hyperuricemia and gout. Medications like allopurinol and febuxostat work by inhibiting this enzyme, thereby reducing the production of uric acid. Research continues to explore the broader implications of xanthine oxidase activity in various physiological and pathological processes.