Structural Insights into the Mechanism of Phosphoenolpyruvate Carboxykinase Catalysis

Taken as a whole, structural data indicate that the PEPCK active site creates an electrostatic environment tailored to stabilize the large amount of localized negative charge that results from close juxtaposition of its multiple anionic substrates. This environment facilitates stabilization of the two transition states as well as the enolate intermediate and allows for efficient catalysis. In concert with this electrostatic environment, unique dynamic properties associated with the reaction pathway allow for the enzyme to minimize off-pathway reactions, such as nucleotide hydrolysis and OAA decarboxylation, that would decrease catalytic fidelity.