Proteomic analysis of human salivary pellet

Human saliva is a bodily fluid very suitable for diagnostic and prognostic purposes. Collection of saliva is economical, safe and easy and it can be performed without the help of health-care staff. It is considered an acceptable and non-invasive process by patients because it does not provoke any pain and so can be easily collected for patients in the pediatric age range [1]. Proteomic study of human whole saliva have until now identified more than 2500 peptides and proteins, however few stfidies have been carried out in order to establish the different contribution to the salivary proteome [2,3]. For this reason we have started a proteomic study on the salivary pellet which is obtainable from whole saliva at low g and that mainly comprises exfoliating oral epithelial cells. I mL of whole saliva was centrifuged at 3000 g immediately after collection and the pellet was treated three times with 200 trtL O.IVo trifluoroacetic acid. The soluble fraction was investigated by a top-down HPLC-ESI-MS approach, while the insoluble components were re-suspended in a modified SDS-PAGE loading buffer and separated by monodimensional SDS-PAGE. Lane was cut into 21 sections of the same area and trypsin digested. Preliminary data evidenced different peptides and proteins in the soluble fraction and in the insoluble material