title: Multimolecular salivary mucin complex is altered in saliva of cigarette smokers: detection of disulfide bridges by Raman spectroscopy.
abstract: Saliva contains mucins, which protect epithelial cells. We showed a smaller amount of salivary mucin, both MG1 and MG2, in the premenopausal female smokers than in their nonsmoking counterparts. Smokers' MG1, which contains almost 2% cysteine/half cystine in its amino acid residues, turned out to be chemically altered in the nonsmoker's saliva. The smaller acidic glycoprotein bands were detectable only in smoker's saliva in the range of 20-25 kDa and at 45 kDa, suggesting that degradation, at least in part, caused the reduction of MG1 mucin. This is in agreement with the previous finding that free radicals in cigarette smoke modify mucins in both sugar and protein moieties. Moreover, proteins such as amylase and albumin are bound to other proteins through disulfide bonds and are identifiable only after reduction with DTT. Confocal laser Raman microspectroscopy identified a disulfide stretch band of significantly stronger intensity per protein in the stimulated saliva of smokers alone. We conclude that the saliva of smokers, especially stimulated saliva, contains significantly more oxidized form of proteins with increased disulfide bridges, that reduces protection for oral epithelium. Raman microspectroscopy can be used for an easy detection of the damaged salivary proteins.
authors.affiliation: Department of Functional Biology, Kanagawa Dental College, 82 Inaokacho, Yokosuka 238-8580, Japan. motoe@kdcnet.ac.jp
authors.forename: Motoe
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Junko
authors.initials: J
authors.lastname: Iizuka
authors.forename: Yukari
authors.initials: Y
authors.lastname: Murata
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ito
authors.forename: Mariko
authors.initials: M
authors.lastname: Iwamiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mori
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hirata
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Mukai
authors.forename: Yuko
authors.initials: Y
authors.lastname: Mikuni-Takagaki
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism; D000681:Amylases / Q000378:metabolism; D004136:Dinitrobenzenes / Q000494:pharmacology; D004220:Disulfides / Q000737:chemistry*; D004229:Dithiothreitol / Q000494:pharmacology; D005260:Female; D005609:Free Radicals; D006801:Humans; D018613:Microscopy, Confocal; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism*; D017697:Premenopause; D012463:Saliva / Q000378:metabolism*; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D012737:Sex Factors; D012907:Smoking; D013059:Spectrum Analysis, Raman; D062789:Tobacco Products
chemical_list: D000418:Albumins; D004136:Dinitrobenzenes; D004220:Disulfides; D005609:Free Radicals; D009077:Mucins; D012471:Salivary Proteins and Peptides; D000681:Amylases; C010936:2,4-dinitrothiocyanatobenzene; D004229:Dithiothreitol