In: Essentials of Glycobiology [Internet]. 4th edition. Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 2022. Chapter 9.


N-Glycans are covalently attached to protein at asparagine (Asn) residues by an N-glycosidic bond. Although diverse sugars are attached to Asn in prokaryotes (Chapters 21 and 22), all eukaryotic N-glycans begin with GlcNAcβ1–Asn and are the focus of this chapter. The biosynthesis of N-glycans is most complex in mammals and is described here in detail. Terminal sugars that largely determine the diversity of N-glycans are described in Chapter 14. Glycosylation-mediated quality control of protein folding by N-glycans is presented in Chapter 39, and the mannose 6-phosphate recognition determinant on N-glycans, necessary for targeting lysosomal hydrolases to lysosomes, is described in Chapter 33. Human congenital disorders of glycosylation arising from defects in N-glycan synthesis are discussed in Chapter 45.

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