N-Glycosidase F PNGase

Glycoprotein was digested using the peptide N-Glycosidase F (PNGase F) to release N-linked glycan, then labeled with 8-aminopyrene-l,3,6-trisulfonate (APTS). The detection used LIF with a argon-ion laser. 

Removal of glycans from either the intact glycoprotein or a glycopeptide with the enzyme peptide A-glycosidase F (PNGase-F) leaves aspartic acid in place of the asparagine at the N-linked site of the protein. Consequently, if the peptide sequence is known, the occupancy at the site can be deduced. In cases where the sequence is not known, the aspartic acid can be identified by partial O incorporation if the digestion is performed in 40% O-enriched water. 

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