Protein glycosylation
1. Assembly of the precursor
oligosaccharide…
IMPORTANT POINTS:
Assembly takes place on the
carrier lipid dolichol, anchored in
the ER membane.
A pyrophosphate bridge joins
the 1st sugar to the dolichol.
Sugars are added singly and
sequentially.
After the two N-acetylglucos-
amines are added, the assembly
flips from the cytosolic side to
the ER lumen.
Nine mannose and three
glucose molecules are added,
totaling 14 sugars.