Site-Specific Profiling of Serum Glycoproteins Using N-Linked Glycan and Glycosite Analysis Revealing Atypical N-Glycosylation Sites on Albumin and α-1B-Glycoprotein

Anal Chem. 2018 May 15;90(10):6292-6299. doi: 10.1021/acs.analchem.8b01051. Epub 2018 May 1.


Most serum proteins are N-linked glycosylated, and therefore the glycoproteomic profiling of serum is essential for characterization of serum proteins. In this study, we profiled serum N-glycoproteome by our recently developed N-glycoproteomic method using solid-phase extraction of N-linked glycans and glycosite-containing peptides (NGAG) coupled with LC-MS/MS and site-specific glycosylation analysis using GPQuest software. Our data indicated that half of identified N-glycosites were modified by at least two glycans, with a majority of them being sialylated. Specifically, 3/4 of glycosites were modified by biantennary N-glycans and 1/3 of glycosites were modified by triantennary sialylated N-glycans. In addition, two novel atypical glycosites (with N-X-V motif) were identified and validated from albumin and α-1B-glycoprotein. The widespread presence of these two glycosites among individuals was further confirmed by individual serum analyses.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albumins / chemistry*
  • Glycoproteins / blood*
  • Glycosylation
  • Humans
  • Peptides / analysis*
  • Polysaccharides / analysis*


  • Albumins
  • Glycoproteins
  • Peptides
  • Polysaccharides