Chun-Ming Huang and Wenhong Zhu Pages 521 - 531 ( 11 )
Establishment of a saliva protein/peptide signature will provide important information for clinical diagnostics and prognosis of human disease. We digested human whole saliva with trypsin to create a tryptic digest salivary peptidome. Proteins/peptides were subsequently identified by high throughput tandem mass spectrometry in conjunction with database searching. Sixty-three saliva peptides corresponding to twenty-two saliva proteins were identified. Thirty of sixty-three saliva peptides with non-specific tryptic cleavage sites were derived from proline-rich proteins, mucin 7, statherin and collagen. Several peptides derived from proline-rich proteins exhibit proline (Pro) - glutamine (Gln) C-termini (- PQ C-termini). Seven peptides with -PQ C-termini were identified in undigested whole saliva, suggesting that peptides with -PQ C-termini indigenously exist in human saliva. Peptides with -PQ C-termini are known to bind oral bacteria and exhibit properties characteristic of innate-immunity peptides. Thus, a saliva peptidome containing peptides with -PQ Ctermini, as presented here, may reinforce the development of innate-immunity-related disease monitoring using noninvasive saliva samples and mass spectrometry-based techniques.
Mass spectrometry, peptidome, human whole saliva, tryptic digest
Division of Dermatology, Department of Medicine, University of California, San Diego and VA San Diego Healthcare Center, Rm 3217A, 3350 La Jolla Village Drive, San Diego, CA 92161 USA.