Xantinoxidáz

Xantinoxidáz is an enzyme that plays a crucial role in purine metabolism. Its primary function is to catalyze the oxidation of hypoxanthine to xanthine and then further to uric acid. This process is the final step in the catabolism of purines, which are essential components of DNA and RNA.

The enzyme is predominantly found in the liver and intestinal mucosa of mammals, with significant activity also present in other tissues. Xantinoxidáz is a molybdenum-containing enzyme, meaning it requires molybdenum as a cofactor to perform its catalytic activity. It also contains iron-sulfur centers.

There are two main forms of the enzyme: xanthine oxidase (XO) and xanthine dehydrogenase (XDH). While XO is the predominant form in many tissues, XDH is also present and can be converted to XO under certain conditions, such as oxidative stress. This interconversion is important because XO produces reactive oxygen species (ROS) as byproducts of its reaction, contributing to oxidative damage.

Dysfunction or overactivity of xantinoxidáz can lead to health problems. Elevated levels of uric acid in the blood, a condition known as hyperuricemia, are often associated with increased xantinoxidáz activity. Hyperuricemia can result in the formation of urate crystals in joints, leading to gout, a painful inflammatory condition. Furthermore, the production of ROS by xantinoxidáz is implicated in various inflammatory diseases and cellular damage. Medications that inhibit xantinoxidáz, such as allopurinol, are commonly used to treat gout and hyperuricemia.