Kinetic and Thermodynamic Properties of Bovine Kidney Uricase

Uricase is an important enzyme in the metabolism of purines catalyzing the oxidation of uric acid in the presence of oxygen, producing allantion, H2O2 and CO2. In humans and great apes, uric acid is the final product of the purine catabolism pathway - lower organisms express uricase which further degrades uric acid, however due to nonsense mutations in the urate oxidase gene (UOX pseudogene) it is not expressed in humans. Uricase enzyme was isolated from bovine kidney. The activity of crud uricase noted was3721.04 U/mL and 135.681 U/mg specific activity with 27.426 mg/mL of protein contents. The activity 9581.843 U/mL and specific activity 534.641 U/mg were obtained when enzyme was subjected to ammonium sulfate precipitation technique at 50% saturation. The rate of irreversible thermal denaturation was determined by incubating the Uricase at different temperatures ranging from 37 – 60°C. Half-life decreased from 660 to 149.4 min after heating at 60°C as compared to 37°C. The enzyme had positive ∆S*, ∆H* and ∆G*.