Chemoenzymatic Method for Glycoproteomic N-Glycan Type Quantitation

Area of Science:

• Biochemistry
• Glycobiology
• Proteomics

Background:

• Glycosylation is a critical post-translational modification.
• Existing glycoproteomics methods primarily offer qualitative identification.
• Quantitative analysis of glycoproteins, especially N-glycan types, remains underdeveloped.

Purpose of the Study:

• To develop a quantitative method for analyzing N-glycoproteome based on N-glycan types.
• To enable the quantification of six distinct N-glycan structures per glycopeptide.
• To investigate N-glycan type microheterogeneity in biological samples.

Main Methods:

• A chemoenzymatic strategy combining endoglycosidase specificity and isotope dimethyl labeling.
• Quantification of high-mannose/hybrid, biantennary, and triantennary glycans (with/without core fucose).
• Application of the glyco-TQ method to IgG1 Fc fragment and MCF7 cell line proteins.

Main Results:

• Successful quantification of six N-glycan types on glycopeptides.
• Demonstration of the glyco-TQ method's efficacy on IgG1 Fc fragment.
• Quantitative profiling of N-glycan types in MCF7 cells, revealing glycopeptide and glycoprotein level microheterogeneity.

Conclusions:

• The developed glyco-TQ method offers a novel quantitative strategy for N-glycan type analysis.
• This approach facilitates the evaluation of glycosylation states at specific sites.
• The method has broad applications in cancer biomarker research, pharmaceutical characterization, and vaccine development.