FIG 8.

Reoxidation of photoreduced FAD. Anaerobic FAD (5 μM final) was photoreduced in the presence of 1 mM methionine using a Xenon arc lamp. The reduced flavin was then mixed with oxidant (CuSO₄ or K₂Cr₂O₇) and observed at 450 nm. (A) Reoxidation in the presence of 40, 80, 160, 320, and 640 μM CuSO₄. The inset depicts the dependence of the rates observed based on the fit to equation 3 (dashed line) (B) Reoxidation in the presence of 20, 40, 160, and 320 μM K₂Cr₂O₇ (predominately CrO₄⁼ at pH 8.0). The inset depicts the dependence of the rates observed based on the fit to equation 3 (dashed line).