To probe the mechanism of hydrolysis of GPXs, we studied the reaction of G3PE in the presence and absence of EA at pH 9.5. Upon heating at 40°C, G>P was formed in both instances (Fig. ), confirming its intermediacy. On the other hand, the rate of hydrolysis of G3PE was found to depend on the concentration of EA (Fig. ). As expected, in the presence of EA, G2PE was formed following the reaction of transient G>P with EA (Fig. ). Finally, we observed that, in the absence of EA, the rate of hydrolysis of G3PE is proportional to the pH of the solution (Fig. ). These outcomes reveal that the hydrolysis of G3PE is subject to general and, more importantly, specific base catalysis.