Quantitative Evaluation of O‐Glycosidic Linkages between Sugars and Aminoacids in Ovine Submaxillary Gland Mucoprotein

The O ‐glycosidic nature of almost 85% of the linkages between the prosthetic disaccharides and ‐OH groups of serine and threonine residues has been definitively established in ovine submaxillary gland mucoprotein (OSM). The alkali‐lability of the sugar protein linkages was attributed to a β‐elimination mechanism of the disaccharides and the stoichiometric conversion of serine to dydroalanine and of threonine to α‐amino crotonic acid has been demonstrated in alkali‐treated OSM. Serine and threonine residues are involved within these O ‐glycosidic linkages in equimolecular proportions. Preliminary results concerning the structure of the peptide chain in the vicinity of the prosthetic group linkages are reported.