Cloning, Heterologous Expression, and Characterization of a Neutral Uricase from Arthrobacter sp. CSAJ-16 in Cangshan Mountain

Uricase (or Urate oxidase), a key enzyme involved in purine metabolism, is commonly used in treating conditions such as gout, hyperuricemia, and tumor lysis syndrome. In this study, a uricase-producing strain (named CSAJ-16) was isolated from the soil sample of Cangshan Mountain, Yunnan Province, China. This strain was identified as Arthrobacter sp. CSAJ-16. Based on the gene sequence alignment, the uricase gene (named aruox) of Arthrobacter sp. CSAJ-16 was amplified and heterologously expressed. The recombinant uricase (ArUOX) was about 32 kDa. The optimal pH and temperature of ArUOX were pH 7 and 20°C, respectively. The ArUOX remained above 50% relative activity after incubation at 37°C for 100 min or at pH 6.0–8.6 for 24 h. Moreover, metal ions such as K⁺, Mg²⁺, Ca²⁺, Ba²⁺ and Pb²⁺ can significantly enhance the activity of ArUOX (> 200%). These enzymatic properties indicate that ArUOX has potential applications in pharmaceutical enzymes and uric acid detection kits.