Fig. 1

RP-HPLC chromatogram of a reaction mixture of AcdGuo with uric acid detected at 245 nm. A solution of 100 μM AcdGuo and 400 μM uric acid was irradiated with UV through a 300-nm longpass filter in 100 mM potassium phosphate buffer at pH 7.4 and 37 °C for 10 min. The HPLC system consisted of LC-10ADvp pumps and an SPD-M10Avp UV-Vis photodiode-array detector (Shimadzu, Kyoto, Japan). For RP-HPLC, an Inertsil ODS-3 octadecylsilane column of size 4.6 × 250 mm and particle size of 5 μm (GL Sciences, Tokyo, Japan) was used. The eluent was 20 mM ammonium acetate (pH 7.0) containing acetonitrile. The acetonitrile concentration was increased from 0 to 30% over 45 min in linear gradient mode. The column temperature was 40 °C and flow rate was 1 mL/min