Characterizing, Application And Cloning Of Uricases From Bacillus Fastidious

Serum uric acid assay is a routine work in medical laboratory. The indirect equilibrium method by peroxidase-coupled assay of hydrogen peroxide in common use suffers from interferences from reducing agents and xanthine. Recently, a kinetic uricase method was established for serum uric acid assay by predicting background absorbance with an integrated method (China patent zl 03135649.4). The use of uricase of higher Michaelis-Menten constant (Km) and lower sensitivity to xanthine improved its resistance to xanthine. However, most commercial uricases show higher sensitivity to xanthine besides lower Km. Herein, uricases from Bacillus fastidious were investigated to seek for a desirabel tool enzyme. These works were reported.1. Extracellular uricase was prepared from the medium of Bacillus fastidious (ATCC 26904) by fractionation with ammonium sulfate, and further purified by DEAE-cellulose chromatography. This uricase suited for serum uric acid assay by direct assay of initial absorbance before uricase action and predicting the background absorbance of uricase reaction solution with the integrated method. This uricase was composed of single...