Abstract: Urate oxidase catalyzes the decomposition of uric acid into hydrogen peroxide and allantoin, which has higher solubility, and is commonly used for uric acid detection and treatment of hyperuricemia-related diseases. In this study, a high-yield urate
oxidase-producing strain YHBJ-12 (GenBank accession number ON351059.1) was isolated from sediment samples of Chaka Salt Lake
in Qinghai Province. Based on 16S rRNA gene sequencing and phylogenetic analysis, the strain was identified as Streptomyces sp. Enzymatic properties revealed that the optimal reaction pH for the urate oxidase produced by strain YHBJ-12 was 7.0, and the optimal reaction temperature was 25 °C. The enzyme maintained over 60% relative activity within a pH range of 5.6-8.6 and a temperature range of 15-50 °C, demonstrating good pH stability and thermal stability. It retained high activity under near-human physiological conditions (37 °C, pH 7.0). K⁺, Mg²⁺, and Co²⁺ significantly enhanced enzyme activity, whereas Ba²⁺, Mn²⁺, Pb²⁺, Cu²⁺, and inhibitors including EDTA, SDS, PMSF, and DTT exerted varying degrees of inhibitory effects. These characteristics indicate that the urate oxidase from strain YHBJ-12 possesses potential for further development and application, providing an excellent enzyme source for the development of high-sensitivity uric acid detection reagents and novel urate oxidase preparations.

Key words: uric acid, urate oxidase, enzymatic properties, Streptomyces