Xanthine Oxidase in Biology and Medicine

Abstract

Xanthine oxidoreductase is an enzyme first discovered in milk and extensively characterized over a period of several decades. Because of the availability and relative stability of the enzyme, it ws one of the first flavoproteins to be purified and crystallized. It was also the first mammalian enzyme found to contain molybdenum and iron. Xanthine oxidoreductase had been relegated to the role of a model protein for the study of oxidation-reduction reactions until relatively recently when Granger et al. proposed that xanthine oxidase was a significant biological source of reactive oxygen species and could play an integral role in the tissue injury associated with ischemia-reperfusion.