Figure 1.

An overview of the glycosylation process. (a) Complex carbohydrates are biosynthetically assembled from sugars obtained from dietary sources, from endogenous conversion from other monosaccharides, or from recycling and salvage pathways. Oligosaccharides of various composition can be attached to various proteins embedded in the plasma membrane (1 and 3) or directly to lipids (2). Collectively, these cell-surface sugars (1, 2, and 3) comprise the glycocalyx that gives each cell a unique molecular identity. Oligosaccharides can also be attached to secreted proteins (4). (b) Symbols and abbreviations used in this paper for common sugars (adapted from [36]).