RP-HPLC-ESI-MS evidenced that salivary cystatin B is detectable in adult human whole saliva mostly as S-modified derivatives: S-Glutathionyl, S-cysteinyl and S-S 2-mer

► Cystatin B is detectable in saliva as S-glutathionyl, S-cysteinyl and S-S 2-mer. ► S-unmodified cystatin B is usually not detectable in human adult whole saliva. ► The percentages of S-derivatives have slight inter-individual variations. ► S-derivatives are new PTMs for a salivary protein and for cystatin B. ► These PTMs could have relevance on the quaternary assembly of cystatin B.