Figure 2

Effects of uricase activities on K _m estimated by measuring absorbance at 308 nm in 0.20 M borate buffers at 25°C. Final uric acid concentrations ranged from 0.10 to 0.50 mM at pH 9.2 or 8.2, and from 0.070 to 0.33 mM at pH 7.4. Results were from at least three independent assays with CVs below 12%. Uricase activities were those calibrated with 0.075 mM uric acid at the indicated reaction pH. ^* indicated P < 0.05 versus that at lower uricase activities by Student t-test.