DETERMINATION OF GLYCOSYLATION SITES IN O-LINKED GLYCOPEPTIDES - A SENSITIVE MASS-SPECTROMETRIC PROTOCOL

A sensitive mass spectrometric method for the specific identification of O-glycosylation sites in glycopeptides is presented. Reductive beta-elimination liberates a peptide containing a specifically modified amino acid at the former site of carbohydrate attachment. Mass spectrometry is used to determine the sequence of the modified peptide, in which the position of the modified amino acid marks the site of O-glycosylation. The method also provides information on the carbohydrate chain and is applicable at the low nanomolar level.