Optimized Glycopeptide Enrichment Method-It Is All About the Sauce

Anal Chem. 2022 Jul 26;94(29):10308-10313. doi: 10.1021/acs.analchem.2c00524. Epub 2022 Jun 28.

Abstract

Protein glycosylation is a family of posttranslational modifications that play a crucial role in many biological pathways and diseases. The enrichment and analysis of such a diverse family of modifications are very challenging because of the number of possible glycan-peptide combinations. Among the methods used for the enrichment of glycopeptides, boronic acid never lived up to its promise. While most studies focused on improving the affinity of the boronic acids to the sugars, we discovered that the buffer choice is just as important for successful enrichment if not more so. We show that an amine-less buffer allows for the best glycoproteomic coverage, in human plasma and brain specimens, improving total quantified glycopeptides by over 10-fold, and reaching 1598 N-linked glycopeptides in the brain and 737 in nondepleted plasma. We speculate that amines compete with the glycans for boronic acid binding, and therefore the elimination of them improved the method significantly.

MeSH terms

  • Boronic Acids
  • Glycopeptides*
  • Glycosylation
  • Humans
  • Polysaccharides
  • Proteomics* / methods

Substances

  • Boronic Acids
  • Glycopeptides
  • Polysaccharides