Figure 2.

Anaerobic reduction of 8 μM D170S/T457E by the xanthine/xanthine oxidase system (23) in the presence of 8 μM thionin in 50 mM potassium phosphate buffer (pH 7.5) at 25°C. Spectra were taken at regular time intervals (10 min), and full reduction was achieved after 95 min. The Inset shows the log (E_ox/E_red) (measured at 440 nm after correction for thionin) vs. log (dye_ox/dye_red) (measured at 600 nm) plot.