Effects of recombinant amelogenin on hydroxyapatite formation in vitro

To determine the role of amelogenin in the mineralization of dental enamel, the effects of the recombinant mouse amelogenin rM179 on in vitro hydroxya patite formation have been studied. In a steady-state agarose gel assay for hydroxyapatite nucleation, rM179 lacked significant activity at concentrat ions up to 300 mu g/ml. In an autotitration assay for inhibition of de novo hydroxyapatite formation, rM179 had no significant activity at concentrati ons up to 30 mu g/ml. Using selected-area dark-field electron microscopy, i t was shown that rM179, at concentrations up to 30 mu g/ml, did not signifi cantly affect the length of hydroxyapatite crystals formed in steady-state agarose gels. These findings suggest that amelogenins do not possess the sp ecific crystal-modulating properties characteristic of certain acidic miner alized tissue proteins proteins.