Determination of N– and O-linked site mapping is often a crucial part of glycoprotein characterization.
Enzymatic deglycosylation in the presence of 18O-labeled water results in an 18O label on the site of the recently removed N-glycan. For O-linked glycosylation, BEMAD (β- elimination followed by Michael addition with dithiothreitol) may be used.
Isotopic shift monitoring using LC-MS methodology helps provide information regarding the position and extent of N-linked glycosylation.
