Figure 2.

Time course of the tyrosinase-catalyzed oxidation of EQ 1 and HPLC analyses of reaction products. (a) UV/visible spectral changes of EQ 1 at pH 6.8; (b) UV/visible spectral changes of EQ 1 at pH 5.3; (c) HPLC analysis following the tyrosinase-catalyzed oxidation of EQ 1 at pH 5.3, the reaction being stopped by the addition of NaBH₄, followed by HClO₄; (d) HPLC analysis following the tyrosinase-catalyzed oxidation of EQ 1 at pH 5.3 in the presence of 10 mol eq. AA, the reaction being stopped by the addition of HClO₄. Data for (a,b) were obtained from single experiments, but reproducibility was confirmed for each experiment. Data for (c,d) were obtained from averages of two independent experiments.