Mg2+ and other polyvalent cations catalyze nucleotide fluorolysis

The reaction of fluoride with adenosine triphosphate has been studied as a nonenzymatic analog of the pyruvate kinase-catalyzed fluorokinase reaction. The production of fluorophosphate, as well as adenosine 5'-O-fluorophosphate (FAMP) and adenosine 5'-O-(2-fluorodiphosphate) (betaFADP) was found to be dependent on the presence of polyvalent metal ions. All ions tested showed significant activity. Two catalytic regimes for the cations could be distinguished: a less specific enhancement of product formation at lower fluoride/cation ratios, and a considerably more active and specific (for fluorophosphate production) enhancement at high fluoride/cation ratios. A comparison of the results with studies of cation-catalyzed nucleotide hydrolysis indicates that the fluorolysis mechanisms are analogous to the hydrolysis by hydroxyl ions observed at high pH. In addition to these nonenzymatic studies, experiments performed using several commercially available kinases indicated significant fluorokinase activity for two: glycerokinase and acetate kinase, although the activities were much below that of pyruvate kinase. With the exception of the concentrations used in these studies, these reactions proceed under physiological conditions, yielding products at sufficient concentrations to be readily detected by 19F NMR spectroscopy.