Discussions

Glycan sequencing is one of the main characters of glycopeptide, standing for the monosaccharide sequence and branching. Glycan sequencing can provide an indication of the structure, sequence, and branching of glycan chain, illuminating the protein’s glycosylation profile, microheterogeneity and its activity. Glycosylation has great importance in the development of biological drugs because their glycan chains markedly affect product stability, activity, antigenicity, and pharmacodynamics. Glycan sequences mainly contribute to glycan microheterogeneity.

Technologies for Glycan Sequencing in Creative Biolabs
Mass Spectrometry (MS)
Based on glycan ionization, fragmentation, and mass identification of the fragments, MS analysis is usually used for glycan sequencing. Electrospray ionization (ESI) MS/MS and matrix-assisted laser desorption/ionization (MALDI) MS/MS are two main MS methods for oligosaccharide analysis. Before analysis, the glycan sample must be desalted to prevent ionization masking in ESI and MALDI analysis and fragment ions obtained from permethylated derivatives are easily assignable to glycan sequences. Collision-induced dissociation (CID) is the most common method to form glycan fragmentation. High CID causes glycan cross-ring cleavages, providing data on the monosaccharide linkages; while low CID energy yields glycosidic cleavages, providing data on the monosaccharide sequence and branching. CID MS/MS scans can identify putative glycoforms associated with the same glycosylation site.