ABSTRACT
Urate oxidase, also called uricase or urate oxygen oxidoreductase, is an enzyme of the purine breakdown pathway that catalyzes the oxidation of uric acid in the presence of oxygen to allantoin and hydrogen peroxide through a complex reaction mechanism. In the presence of oxygen, urate oxidase degrades uric acid into 5-hydroxyisourate and hydrogen peroxide. Uricozyme contains a mixture of urate oxidase molecules, one of which is a cysteine adduct on C103. Two different approaches have been used for measuring urate oxidase activity. The first one is based on monitoring substrate decrease, and the second is based on monitoring product increase. Evolutionary genetic mutations have resulted in the loss of gene expression for urate oxidase in humans; with the result that uric acid is the end product of the catabolism of purines. The urate oxidase-encoding sequence used for urate oxidase production in yeast was isolated from an Aspergillus flavus complementary deoxyribonucleic acid library, using synthetic oligonucleotides as probes.
