Calcified Tissue International

, Volume 44, Issue 3, pp 200–208

Osteonectin inhibitingde novo formation of apatite in the presence of collagen

Authors

  • Y. Doi
    • Department of Dental Materials and Technology School of DentistryAsahi University
  • R. Okuda
    • Department of Pedodontics, School of DentistryAsahi University
  • Y. Takezawa
    • Department of Dental Materials and Technology School of DentistryAsahi University
  • S. Shibata
    • Department of Dental Materials and Technology School of DentistryAsahi University
  • Y. Moriwaki
    • Department of Dental Materials and Technology School of DentistryAsahi University
  • N. Wakamatsu
    • Department of Dental Materials and Technology School of DentistryAsahi University
  • N. Shimizu
    • Department of Pedodontics, School of DentistryAsahi University
  • K. Moriyama
    • Department of Orthodontics School of DentistryTokyo Medical and Dental University
  • H. Shimokawa
    • Department of Biochemistry, School of DentistryTokyo Medical and Dental University
Laboratory Investigations

DOI: 10.1007/BF02556565

Cite this article as:
Doi, Y., Okuda, R., Takezawa, Y. et al. Calcif Tissue Int (1989) 44: 200. doi:10.1007/BF02556565

Summary

The effect of bone matrix protein of osteonectin onde novo formation of apatite was studied in a wide range of calcium phosphate solutions in the presence of collagen. In every solution, from which amorphous calcium phosphate, octacalcium phosphate, or apatite precipitated as a possible initial phase, osteonectin at concentrations less than 1 μM retarded the precipitation, subsequent transformation to apatite, and ripening crystal growth of apatite. Collagen present as either reconstituted or denatured form had no effect on the osteonectin-associated reactions as well as osteonectin-free reactions, and no structural correlation was observed between collagen fibrils and any of the calcium phosphates that appeared in our system. Direct measurement of free calcium levels in the solutions suggested that the reduction in calcium activity due to complexing with osteonectin hardly explained the inhibitory activity of osteonectin in retarding the formation of apatite. Instead, our transmission electron microscopic (TEM) observation strongly suggested that the primary mechanism for osteonectin to inhibit the formation of apatite is to block growth sites of calcium phosphates nucleated. The apatite thus formed in the presence of osteonectin showed less resolved X-ray diffraction patterns, partly because of smaller crystallites as suggested by TEM.

Key words

OsteonectinCalcificationBone matrix proteinCollagenApatite

Copyright information

© Springer-Verlag 1989