Once the precursor oligosaccharide is formed, the completed glycan is then transferred to the nascent polypeptide in the lumen of the ER membrane. This reaction is driven by the energy released from the cleavage of the pyrophosphate bond between the dolichol-glycan molecule.
There are three conditions to fulfill before a glycan is transferred to a nascent polypeptide:
*Asparagine must be located in a specific consensus sequence in the primary structure (Asn–X–Ser or Asn–X–Thr or in rare instances Asn–X–Cys).
*Asparagine must be located appropriately in the three-dimensional structure of the protein (Sugars are polar molecules and thus need to be attached to asparagine located on the surface of the protein and not buried within the protein) 
*Asparagine must be found in the luminal side of the endoplasmic reticulum for N-linked glycosylation to be initiated. Target residues are either found in secretory proteins or in the regions of transmembrane protein that face the lumen.
Oligosaccharyltransferase is the enzyme responsible for the recognition of the consensus sequence and the transfer of the precursor glycan to a polypeptide acceptor which is being translated in the endoplasmic reticulum lumen. N-linked glycosylation is, therefore, a co-translational event