Structural studies on a sulphated glycoprotein preparation isolated from human saliva

Structural Probe Analysis on the Attachment of Salivary Glycoproteins to Hydroxyapatite Using Fourier-Transformed Infrared Spectroscopy

“…Another strong absorp tion is present between 1,230 and 1,250 cm-1 due to the S = 0 stretching of the sulphate groups present in the molecule. O f particular interest are the absorp tions at 775 and 828 cm' 1 and a suggested shoulder at 1,000 cm '1, which result from the equatorial configu ration of the -O S O 3H groups in the 6-position o f the galactopyranose ring of the carbohydrate component [Lloyd et al, 1961] and confirms our earlier findings that the sulphated component of the glycoprotein is N-acetylgalactosamine 6-O-sulphate [Green and Embery, 1985]. None of the features appear with any in tensity in the hydroxyapatite preparation, thus pre venting any masking effect in the interpretation o f the reacted and unreacted spectra ( fig.…”

“…It contained blood group A activity, was able to aggregate cells o f Streptococcus sanguis, strains N C T C 7864 and 7863, but not cells o f Streptococcus mutans strains O M Z61, HS6 or LM 7, reacted with hydroxyapatite and was able to inhibit the adhesion o f gingival fibroblast-like cells to plastic surfaces ). The sulphated component was shown by acid hydrolysis studies, infrared spectra and chromatography to be Nacetylgalactosamine-6-O-sulphate [Green and Embery, 1985).…”

“…Similarly the characteristic absorption at 1,230-1,250 cm' 1 is also lost, both observations indicating that the sulphate groups are intimately involved in attachment of the sulphated glycoprotein to the hydroxyapatite surface. Since the sulphate groups are known to be covalently linked to the carbohydrate apo-protein components, predominantly as N-acetylgalactosamine 6-O-sul phate [Green and Embery, 1985], it seems almost cer tain that the carbohydrate residues attach to the hy droxyapatite. Evidence in support o f this arises from the chemical identification of hexosamine O-sulphates as the apatite-binding regions of certain saliv ary glycoproteins .…”

Glycosylation Pattern and Cell Attachment‐Inhibiting Property of Human Salivary Mucins

“…[1][2][3][4] In those studies Muc was prepared by gel filtration of WHS and was not formally identified as the well-characterized salivary mucin MG1. However, both structural and functional similarities of Muc and MG1, 5,6 and the present observation of cell attachmentinhibiting property of the material isolated from WHS by ultracentrifugation, which is one of the standard isolation methods for MG1, 18,25 suggest strongly that Muc and MG1 are biochemically and functionally identical or at least very similar salivary constituents. This is supported by the high MW of Muc as confirmed by SDS-AGE (Fig.…”

“…This property of WHS is mediated by its high molecular weight sulfated mucin glycoprotein fraction (Muc), [1][2][3] which in many ways is closely similar to the well-characterized 5 salivary mucin MG1, such as its molecular weight, electrophoretic behavior, blood group activity, glycosylation, and sulfation. 3,6 Partial characterization of Muc 3 defined this salivary constituent as a heterotypic complex of anionic high molecular weight sulfated glycoproteins, which retains its complex structure and cell attachmentinhibiting property after adsorption to and desorption from hydroxyapatite. Further fractionation of Muc showed that its cell attachment-inhibiting property is conveyed by the most anionic fraction with the molecular weight >300 kDa.…”