Submaxillary glycoproteins

Blix (8, 9, 10) after mild acid hydrolysis of bovine submaxillary glycoprotein isolated a crystalline material called sialic acid which gave the direct and indirect Ehrlich reactions. Table I shows that similar substances were isolated by other workers from glycolipids (11, 12), other... 

Direct proof for the existence of O-glycosidic linkages involving the hydroxyl groups of serine and threonine was provided simultaneously from three laboratories. Anderson et al. (39) reported partial losses of serine and threonine after treatment with 0.52V NaOH (or 0.452V KOH) at 4°C or room temperature for about 20 hours. Subsequent reduction with platinum showed formation of some alanine and < -aminobutyric acid. Harbon et al (40) treated ovine submaxillary glycoprotein at pH 12.8 for 45 minutes at 70 °C. The serine and threonine content decreased by 78 and 60%, respectively. Treatment of this product with 0.1M sulfite, (pH 9, 24 hours, room temperature) caused a conversion of the dehydroserine residues to cysteic acid, but had no action on the dehydrothreonine residues. This reaction has been further studied by Simpson et al. (41). 

Carlson (6) had shown earlier that porcine submaxillary glycoproteins (PSM) produced five reduced oligosaccharides after alkaline borohydride treatment (conditions 0.05M KOH, M NaBH4 at 45°C for 15 hours) removal of more than 90% of the side chains was reported. The oligosaccharides were separated and varied in size from mono to pentasaccharides. Katzman and Eylar (50) found similar but not identical oligosaccharides to be present in PSM, prepared by a different method. 

R. L. Katzman and E. H. Eylar, The isolation and characterization of a trisaccharide from porcine submaxillary glycoproteins, Biochem. Biophys. Res. Commun., 23 (1966) 769-774. 

Bovine submaxillary glycoprotein Cephalosporin C and related compounds... 

Baig, M. M., and Aminoff, D., 1972, Glycoproteins and blood group activity oligosaccharides of serologically inactive hog submaxillary glycoproteins, J. Biol. Chem. 247 6111-6118. 

Figure 47-2. Structures of two 0-linked oligosaccharides found in (A) submaxillary mucins and (B) fe-tuin and in the sialoglycoprotein of the membrane of human red blood cells. (Modified and reproduced, with permission, from LennarzWJ The Biochemistry of Glycoproteins and Proteoglycans. Plenum Press, 1980.)...

Neeser and Schweizer introduced 4 M CF3CO2H for 1 h at 121° for hydrolysis of glycoproteins. Both neutral and amino sugars were considered. They compared this method to hydrolysis with 0.6 M hydrochloric acid for 4 h at 100° and 3 M hydrochloric acid for 0.75 h at 125°. Hydrolysis of fetal-calf-serum fetuin, bovine submaxillary mucin, and horse-radish peroxidase showed hydrolysis with CF3CO2H to be superior. 

L-Cysteic acid residues were produced within the peptide chain when submaxillary-gland glycoprotein from sheep was treated with alkali (pH 9.0), during 24 hours at room temperature in the presence of sulfite (0.1 M). The yield was —55% on the basis of the L-serine decomposed, and the corresponding derivative from L-threonine was not detected.167... 

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