N-glycosylation

The process wherein the glycan chain Glc₃Man₉GlcNAc₂ is transferred from the lipid-linked oligosaccharide to a nitrogen atom (N) of an asparagine residue in a newly synthesized protein in the ER; the asparagine must be part of Asn-X-Ser/Thr consensus sequence for the glycosylation to occur. After attachment, the N-glycan chain undergoes further modifications in the ER and the Golgi to yield a mature N-glycoprotein.