Study of Frozen Storage Conditions Impacting on Salivary Peptidomic by High Resolution Tandem Mass Spectrometry
Abstract The salivary peptidomics provides a new method for study of disease biomarkers, but the effect of frozen storage conditions on the analysis results is not very clear. In this study, peptides in human saliva were separated and enriched by using graphene-lanthanide composite nanomaterial (LaGM), then identified by nano liquid chromatography-high resolution tandem mass spectrometry (Nano LC-HR-MS/MS). The salivary peptidomics were analyzed after the saliva samples were stored at −20 °C and −80 °C for six months respectively. A total of 429 peptides which belong to 33 proteins stored at −80 °C and 595 peptides corresponding to 31 proteins stored at −20 °C, were identified. Compared with −80 °C, the “new” saliva peptides were mainly from degradation of existed peptides. In addition, some salivary proteins were also degraded in some degree at −20 °C. This study illustrated that frozen storage conditions had effect on salivary peptidome, suggesting saliva sample should not be stored at −20 °C for long time when used for peptidomics analysis.