Biochemistry of Monofluorophosphate

Abstract

Monofluorophosphate (MFP) can be synthesized in vitro by the transfer of a phosphoryl group from ATP to F^-, catalyzed by pyruvate kinase, or by the autocatalytic transfer of a phosphoryl group from the enzyme phosphoglucomutase. There is, however, no evidence that MFP is a normal intermediate in cell metabolism. MFP can be degraded by both alkaline and acid phosphatases, and the mechanism is probably similar to the hydrolysis or transfer of phosphoryl groups from other phosphatase substrates. MFP competitively inhibits pyruvate kinase and alkaline phosphatase, and irreversibly inhibits phosphorylase phosphatase. The possibility that impurities or hydrolysis products are responsible for reported effects makes the interpretation of many inhibition studies difficult. The widespread therapeutic use of MFP presents a strong case for a more detailed study of its metabolism.

In vivo Remineralization by a Monofluorophosphate Dentifrice as Determined with a Thin-section Sandwich Method

“…The mechanism whereby brushing the sections of enamel with a monofluorophosphate dentifrice inhibited further demineralization or promoted remineralization was not addressed by this study. However, it is likely that the fluoride ion is importantly involved, since the monofluorophosphate ion is rapidly hydrolyzed in vivo to ionic fluoride by phosphatase enzymes (Pearce, 1983). Overall, 75% of the lesions brushed with the monofluorophosphate dentifrice had a net mineral gain, whereas 60% of the placebo-treated lesions had mineral loss.…”

The Effect of pH, Temperature and Plaque Thickness on the Hydrolysis of Monofluorophosphate in Experimental Dental Plaque

“…The susceptibility of monofluorophosphate (MFP) to enzymic degradation has been known for some time [reviewed by Pearce, 1983]. In the mouth this activity is thought to be brought about by non-specific alkaline phosphatase of bacterial origin, since sterile duct saliva has no demonstrable alkaline phosphatase activity [Chauncey et al, 1963].…”

The effect of monofluorophosphate implant in white rat mothers towards the level of fluor in the incisors of their young babies (Rattus-rattus)

“…PLA in the form of monolith actually has several characteristics, such as: small degradation constant, bio-erosion, and low permeability. 9 Thus, if the reason of the use of MFP is because of anti-caries activities in MFP with its toxicity about one third lower than that in NaF, 3 it still can be degraded by alkali or acid phosphate through hydrolysis process, 5 and by the substitution of the structure of phosphate hydrogen on hydroxy apatite with monofluorophosphate ion. 6 The average of fluoride contained on the incisors of those thirty-five day old white rat babies and the binding of fluoride ion on the teeth, actually depends on the level of fluoride in their blood plasma.…”

“…3 MFP is chosen because it has anti-caries, its toxicity about one third lower than that in NaF, 4 it still can be degraded by alkali or acid phosphate through hydrolysis process, 5 and by the substitution of the structure of phosphate hydrogen on hydroxy apatite with monofluorophosphate ion. 6 The dissolution of MFP will 20 times faster if the level of calcium ions is so high to make calcium-monofluorophosphate compound that easily dissolved.…”