Figure 3. Sketch of the free energy profile for the whole mechanism.

Activation free energies () for all the steps of the mechanism under analysis. Data for the direct reaction are shown in red while those of the reverse reaction are shown in blue. Letters a to g denote the species presented in Fig. 2. The highest point of the profile corresponds to the transition state for the tautomerization of FADH (conversion from b to c of Fig. 2). The largest barrier corresponds to the ring closure into the furanose form (conversion from d to e of Fig. 2).