Salivary proteins such as statherin (STN) are known to be involved in enamel de/remineralisation, the inhibition of crystal growth, and spontaneous precipitation of calcium phosphate salts. The active N-terminal of STN (STN21) is involved in binding with Ca2+ and in reducing HA demineralisation. In addition, salivary Histatin-1 (HTN) inhibits crystal growth of calcium phosphate salts but does not inhibit their spontaneous precipitation. These salivary peptides do not occur as individual molecules in saliva, they are part of a complex salivary system. The aims were to investigate the effect of salivary STN, HTN and their 21 N-terminal peptides (STN21, and HTN21) individually and when in combination on the demineralisation rates of HA and enamel using scanning microradiography. In addition, to understand their effect on HA and enamel demineralisation, peptide adsorption onto HA and enamel was measured spectrophotometrically. Also, peptide aggregation, surface charge and, conformation in solution were investigated. The adsorption and demineralisation reduction of non-human STN was also investigated. STN, HTN and STN21 individually showed similar adsorption and demineralisation reduction efficacy in HA but not in enamel. HTN21 showed the lowest demineralisation reduction of all peptides. STN21 when in combination with either HTN, or HTN21, showed the greatest demineralisation reduction of all peptides. The increase in peptides demineralisation reduction efficacy when in combination suggests co-operative efficacy, which is further increased with the removal of the C-terminal. All individual peptides were found to adopt an α-helical conformation at the N-terminal, which is important in peptide adsorption onto HA surfaces. When in combination conformational changes led to peptide interaction and caused an increase in their net negative charges. In conclusion, it was found that the degree to which demineralisation is reduced by peptides is correlated with the amount of peptide adsorbed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:766151 |
| Date | January 2018 |
| Creators | Almandil, Huda Barak A. |
| Publisher | Queen Mary, University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://qmro.qmul.ac.uk/xmlui/handle/123456789/39743 |
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