Mild tagging procedures for the structural analysis of glycans

Area of Science:

• Carbohydrate Chemistry
• Bioconjugation Chemistry
• Analytical Chemistry

Background:

• Reductive amination is a common method for tagging biomolecules.
• Existing methods may require harsh conditions or have incomplete reduction steps.
• Mild and efficient carbohydrate labeling is crucial for structural analysis.

Purpose of the Study:

• To investigate reductive oxyamination as a mild alternative to reductive amination for glycan tagging.
• To synthesize and evaluate novel hydroxylamine derivatives for improved carbohydrate labeling.
• To assess the suitability of these methods for labeling complex carbohydrates like glycosaminoglycans.

Main Methods:

• Investigated reductive oxyamination of model glycan structures.
• Synthesized novel O- and N-substituted 7-hydroxycoumaryl- and 3-methoxybenzylhydroxylamines.
• Coupled synthesized hydroxylamines with model saccharides under mild, aqueous conditions.
• Analyzed fluorescent derivatives using chromatography and mass spectrometry.

Main Results:

• Oxime formation was quantitative in the developed procedures.
• Reductive hydroxyamination with novel derivatives showed quantitative coupling.
• Fluorescent carbohydrate derivatives exhibited good chromatographic and mass spectrometric properties.
• The reduction step in initial oxyamination attempts was not always complete.

Conclusions:

• Developed mild, aqueous procedures for carbohydrate labeling via oxime formation and reductive hydroxyamination.
• Novel fluorescent hydroxylamine derivatives enable efficient tagging of carbohydrates and oligosaccharide fragments.
• These methods are suitable for labeling complex glycosaminoglycans such as heparin and heparan sulfate.