| 1555 Toward Cataloguing the Proteome and Peptidome of Human Parotid Saliva | ||
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M. HARDT1, L.R. THOMAS1, S.E. DIXON1, S.C. HALL2, H.E. WITKOWSKA2, and S.J. FISHER1, 1University of California - San Francisco, USA, 2University of California - San Francisco, Department of Stomatology, USA Introduction: Saliva is an important determinant of oral health. Alterations in the composition of the oral flora and/or immune dysfunction are often linked to common oral diseases. In turn, changes in salivary composition correlate with disease susceptibility and/or progression. Hence, human saliva is a potential source of novel diagnostic markers and therapeutic targets. Objectives: The aim of this ongoing project is to map the proteins and peptides in parotid saliva as a step toward the goal of cataloguing the human salivary proteome. Methods: Parotid saliva was collected as the ductal secretion. For protein analysis, samples were subjected to 2D-SDS-PAGE and protein spots were identified by peptide mass fingerprinting and tandem mass spectrometry. To analyze native salivary peptides, the low-molecular-weight (LMW) fraction was prepared by ultrafiltration and the filtrate was analyzed by tandem mass spectrometry, both as a mixture and after nano-HPLC separation. Results: Proteins identified in parotid saliva include known constituents, their isoforms and fragments, and several novel components. The LMW fraction proved to be rich in peptides, with fragments of proline-rich proteins and histatins in high abundance. The majority of peptides appeared to be novel and their biological functions are currently under investigation. Finally, we identified a novel histatin peptide octamer - the shortest histatin peptide with candidacidal activity reported to date. Conclusion: By using conventional (e.g., 2D-SDS-PAGE) and relatively unconventional (e.g., ultrafiltration) separation approaches coupled with mass spectrometric identification of the products, we obtained complementary views of the human parotid saliva proteome. The results revealed novel components as well as a surprising number of isoforms and protein fragments. Ongoing rigorous characterization of these protein constituents will increase our understanding of normal physiological and pathological processes in the oral cavity and may lead to the discovery of potential biomarkers that correlate with oral health and conversely, with oral diseases. | ||
| Seq #192 - Salivary Proteomics 10:45 AM-12:45 PM, Friday, 11 March 2005 Baltimore Convention Center 322-323 | ||
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