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Home > Services > Glycomics Service > O-Glycan Profiling Service

O-Glycan Profiling Service

Glycosylation is the one of the most challenging post-translational modifications. It usually has a set of modifications instead of a single modification. Even a single glycosylated site on a peptide may have a number of glycan isoforms with different chain length and branches attached. O-glycans attach to a polypeptide mainly through a glycosidic bond between the terminal monosaccharide residue and the OH group of Serine or Threonine. Unlike N-glycans, there is no known O-linked amino acid consensus sequence yet. The O-glycans are structurally diverse. They can be divided into several structural families with relatively heterogeneous core structures.

O-Glycan Profiling ServiceFigure 1. Different core structures of N-linked glycans

So far no universal enzyme can remove the majority of O-linked glycans, unlike N-glycans. The O-glycanase only removes unsubstituted disaccharide O-GalNAc initiated glycans. Chemical release is usually the method of choice for O-glycan release. The O-glycans are released from the O-glycopeptides mainly by β-elimination.

O-Glycan Profiling ServiceFigure 2. The general procedure of sample preparation for Glycan profiling

O-glycans profiling is usually performed using MALDI-TOF MS. It is necessary to derivatize O-glycan by permethylation to transform all hydroxyl groups into methyl ethers and stabilizes sialic acids by methyl esterification of their carboxyl groups. This allows MALDI TOF MS to analyze of all O-glycans in the positive mode. Direct infusion of O-glycans of permethylation into the mass spectrometer can provide information about glycans composition.

O-Glycan Profiling ServiceFigure 3. Example of O-Glycan structures detected and analyzed by using MS

As one of the leading companies in the omics field with over years of experience in omics study, Creative Proteomics provides glycomics analysis service customized to your needs. Contact us to discuss your project.

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