Mass spectrometric identification and characterization of sialylated O-linked glycopeptides using TiO_(2)-enrichment combined with enzymatic and chemical deglycosylation.

摘要

It is possible to enrich for sialylated O-linked glycopeptides using TiO_(2). beta-eliminated, O-linked glycopeptides does not fully convert back to Serine and Threonine in LC-MS/MS and it is therefore possible to identify formerly sialylated glycopeptides with high confidence using beta-elimination. The combination of TiO_(2) chromatography with high accuracy CID and HCD fragmentation on an LTQ-Orbitrap Velos and chemical beta-elimination is highly favorable for identification and characterization of sialylated O-linked glycopeptides. It seems that Endo D/H treatment is unable to cleave the bond of an O-linked HexNAc. The use of ETD did not enhance the ability to identify and characterize the sialylated O-glycosylated peptides.