Figure 6.

Kinetics of product formation in F₃Y^•-β2 in the presence of TR/TRR/NADPH at (A) 25 °C and (B) 5 °C. The averages of 2–4 separate trials are shown. Data were fit to a two-phase model with the rate constants given in Table 1. The insets show dCDP formation during the first (A) 0.8 s and (B) 2.5 s. The burst phase represents the very first turnover by an α/β pair. Reverse PCET regenerating F₃Y^• is rate-limiting during steady-state turnover.