Phosphoproteins of bovine dentin: evidence for polydispersity during tooth maturation.

The ethylenediaminetetraacetic acid extractable phosphoproteins of dentin from very young fetal calves consisted principally of a monodisperse species with an apparent molecular weight of at least 94 000 and a phosphorus content of 8.0% (w/w). In contrast, the soluble phosphoproteins extracted from mature adult animals under identical conditions ranged in molecular weight from 18000 to 94000 and contained less phosphorus. The data support the conclusion that the phosphoproteins of bovine dentin are degraded in vivo during mineralization and maturation of the tissue.