Alkaline phosphates catalysis in ultrasensitive to charge sequestered between the active site zinc ions

A series of alkaline phosphates (AP) substrates with similar geometries but systematically varying charge on the nonbridging oxygen atom is investigated to determine the energetic properties of the electrostatic interaction between the Zn(super 2+) bimetallocluster and the nonbridging oxygen atom. There is electrostatic repulsion between the two Zn(super 2+) ions bound only 4 angstrom apart and this close spacing within the active site renders it difficult to effectively solvate the metallocluster.