Figure 3.

The pH-dependence of the first-order rate constant of decomposition measured at 250 nm (mean ± SEM, n ≥ 3, all R² values >0.995 for 1 and >0.98 for 2) of 1 (A, 100 μM) and 2 (B, 100 μM) at 37 °C in PBS containing 50 μM DTPA and adjusted to the indicated pHs as necessary by adding NaOH or HCl; measured pH was the same at the end of each kinetic run as it was at time zero.