Chemical Synthesis of Proline-rich and Glutamine-rich Peptides from Amelogenin for Biomimetic Tooth Repair

Dental caries and cavities affect nearly everyone and considered as major public health issues around the world. Dental demineralization occurred when tooth enamel is exposed to acid produced by cariogenic oral bacteria. Once damaged, enamel mineralization cannot be biologically regenerated as it is unable to heal and repair itself. Despite some risk and controversies, for preventing carries fluoride is used as a key ingredient. Peptide-based healing and repairing from Amelogenin protein received great attention for preventing dental caries and cavities. Amelogenin is the most abundant protein in tooth enamel and has a role in the development of enamel rods during the tooth development. The long-term goal of this research is to develop peptide based dental products including toothpastes and dental gels to repair early states of caries and cavities. In this study, two peptides, which are rich in proline and glutamine, from Amelogenin protein were synthesized using the solid phase peptide synthesis protocol. The synthesis of peptides was carried out on a CEM Liberty Blue peptide synthesizer utilizing rink amide resin, which has a loading capacity of 0.65 mmol/g and a mesh size range of 100-200. After peptide synthesis, a mixture of TFA, water, and TIPS was used to cleave the peptide from the resin support. Vacuum filtration was used to isolate the cleaved peptide, and cold ether was added to precipitate it. In LC-MS experiments, the proline rich peptide (LPPQPPLPPM) was eluted at 3.49 mins. Two strong peaks are noticed for this peptide at m/z 1085.65 and 543.58 which correspond to [M+H]+ and [M+2H]2+ charge states. The glutamine-rich peptide (QPQPVQPQPHQPMQP) was eluted at 3.49 mins and related peaks detected at m/z 1958 and 979 which correspond to [M+H]+ and [M+2H]2+ charge states. Future investigations will be carried out for remineralization of these peptides by adding calcium and phosphate ions