Role of associated and covalently bound lipids in salivary mucin hydrophobicity: Effect of proteolysis and disulfide bridge reduction

B. L. Slomiany, V. L.N. Murty, J. Sarosiek, J. Piotrowski, A. Slomiany

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

The hydrophobic properties of salivary mucus glycoprotein were investigated by fluorescence spectroscopy using bis(8-anilino-1-naphthalene-sulfonate). The mucin, purified from rat submandibular salivary gland, was subjected to removal of associated and covalently bound lipids, degradation with pronase, and reduction with β-mercaptoethanol, and titrated with the probe. Analyses of fluorescence data revealed the presence of 49 ± 5 hydrophobic binding sites in the intact mucin molecule, a 69% increase in the number of binding sites occurred following extraction of associated lipids, while the removal of covalently bound fatty acids caused a 25% decrease in the binding sites. Proteolytic destruction of the nonglycosylated regions of the glycoprotein essentially abolished the probe binding, whereas reduction produced glycoprotein subunits whose combined number of hydrophobic binding sites was 2.4 times greater than that of mucus glycoprotein polymer. The results suggest that associated and covalently bound lipids contribute to hydrophobic characteristics of salivary mucin and that the hydrophobic binding sites reside on the nonglycosylated regions of this glycoprotein buried within its core.

Original languageEnglish (US)
Pages (from-to)1046-1053
Number of pages8
JournalBiochemical and Biophysical Research Communications
Volume151
Issue number3
DOIs
StatePublished - Mar 30 1988
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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