Fluoride-binding by organic matrix from early and late developing bovine fetal enamel determined by flow-rate dialysis

Flow-rate dialysis was used to measure the fluoride-binding characteristics of the organic matrix from bovine fetal enamel. The matrix from newly deposited enamel had 5.78 × 10 −5 mol/g protein of high-affinity binding sites for fluoride (F) with a dissociation constant of 1.1 × 10 −6 M. The matrix from enamel in late stages of mineralization had 4.36 × 10 −5 mol/g matrix protein of binding sites with a dissociation constant of 3.2 × 10 −6 M. In the physiologic range of F concentrations, F bound by the early matrix could account for up to 40 times the F bound per unit weight of enamel by late matrix. Early enamel matrix may buffer the newly deposited enamel against transitory fluctuations in local F concentrations.