Figure 1.

Proposed thermodynamic landscape of the PCET pathway at 25 °C and pH 7.6. The overall reaction is proposed to be thermodynamically uphill and driven forward by the rapid irreversible loss of water from NDP substrate in the active site of α2. No direct evidence is available for the presence of a discrete W₄₈ radical intermediate. Studies performed on NO₂Y₁₂₂•-β2 determined the relative reduction potentials of Y₃₅₆, Y₇₃₁, and Y₇₃₀.