Saliva plays many biological roles, from lubrication and digestion to regulating bacterial andleukocyte adhesion. To understand the functions of individual components and families of molecules, itis important to identify as many salivary proteins as possible. Toward this goal, we used a proteomicapproach as the first step in a global analysis of this important body fluid. We collected parotid saliva asthe ductal secretion from three human donors and separated the protein components by two-dimensionalSDS-polyacrylamide gel electrophoresis (2D SDS-PAGE). Proteins in gel spots were identified by peptidemass fingerprinting, and the results were confirmed by tandem mass spectrometry of selected peptides.Complementing this approach we used ultrafiltration to prepare a low-molecular-weight fraction of parotidsaliva, which was analyzed directly or after reversed phase high-performance liquid chromatographyseparation by using mass spectrometric approaches. MS analyses of 2D SDS-PAGE spots revealed knowncomponents of saliva, including cystatins, histatins, lysozyme, and isoforms and/or fragments of
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-amylase,albumin, and proline-rich proteins. We also discovered novel proteins, such as several isoforms of Zn-
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-2-glycoprotein and secretory actin-binding protein. MS analyses of the ultrafiltrate showed that thelow-molecular-weight fraction of parotid saliva was peptide-rich, with novel fragments of proline-richproteins and histatins in abundance. Experiments using
Candida albicans as the test organism showedthat at least one of the novel peptides had antifungal activity. Our results show that saliva is a rich sourceof proteins and peptides that are potential diagnostic and therapeutic targets.