Saliva as a source of new phosphopeptide biomarkers: Development of a comprehensive analytical method based on shotgun peptidomics

Publication date: 1 June 2018
Source:Talanta, Volume 183
Author(s): Giorgia La Barbera, Anna Laura Capriotti, Chiara Cavaliere, Francesca Ferraris, Carmela Maria Montone, Susy Piovesana, Riccardo Zenezini Chiozzi, Aldo Laganà
The paper describes the development of an enrichment method for the analysis of the endogenous phosphopeptides in saliva. The method was based on magnetic solid phase extraction by a magnetic graphitized carbon black-TiO2 composite material and was developed considering different saliva pre-treatments, namely C18 solid phase extraction for purification, direct dilution in loading buffer or acetonitrile precipitation. The method was based on a shotgun proteomics workflow and the enriched peptide mixture was analysed by nanoHPLC and high resolution tandem mass spectrometry. Acetonitrile precipitation provided the best results, with up to 165 endogenous phosphopeptides identified in saliva samples from healthy individuals. The physico-chemical features of the identified endogenous phosphopeptides indicated that such peptides were large, hydrophilic and basic.

Graphical abstract

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