Synthetic Glycosides as Primers of Oligosaccharide Biosynthesis and Inhibitors of Glycoprotein and Proteoglycan Assembly

With the exception of hyaluronic acid, all mammalian saccharides assemble while attached to a lipid or protein primer. Several cases are now known in which oligosaccharide synthesis will occur on synthetic glycoside primers added to cells. A protocol is described in this unit in which b-D-xylosides initiate glycosaminoglycan (GAG) synthesis by substituting for endogenous xylosylated core proteins. At high concentration xylosides will also prime oligosaccharides that resemble glycolipids. N-acetyl-a-D-galactosaminides initiate the synthesis of O-linked oligosaccharides found on mucins and other glycoproteins in an analogous manner. Even disaccharides, such as peracetylated N-acetyllactosaminide, can act as primers. Because these primers compete with endogenous substrates, they also act as inhibitors of proteoglycan (PG) and glycoprotein synthesis. Thus, primers have utility for studying the biological activity of glycoconjugates in cells, tissues, and animals. This unit describes procedures for using glycoside primers in cell culture.