The Effect of Acidic and Amidic Osteocalcin Derived Peptides on the Formation of Nano-hydroxyapatite Crystals

The aim of this study is to investigate the relationship between the structure and function of an osteocalcin derived peptide on hydroxyapatite nanocrystal formation. For this purpose،، a natural motif sequence consisting of 13 amino acids present in the first helix of osteocalcin was selected based on its calcium binding ability and synthesized in both acidic and amidic forms using solid phase method. Circular dichroism (CD) and electron microscopy were performed to examine the structure and function of synthesized peptides. Moreover، the effect of these peptides on the viability of osteoblast cells was evaluated. Electron microscopy analysis showed the formation of plate-like HA nanocrystals in the presence of amidic peptide. In contrast، amorphous calcium phosphate was formed in the presence of acidic peptide. CD spectra analysis confirmed the random coil structure with lower molar elipticity for amidic peptide. In addition، the amidic peptide significantly increased the proliferation of osteoblast cells. It is concluded that increased bioactivity، which only occurred in amidic peptide is attributable to C-terminal amidation. It is also proposed that peptides with the ability to promote HA formation have the potential to be utilized in hard tissue regeneration high bioactivity and biocompatibility.