Characterization of a novel modification on IgG2 light chain. Evidence for the presence of O-linked mannosylation

J Chromatogr A. 2007 Jul 13;1156(1-2):183-7. doi: 10.1016/j.chroma.2007.04.050. Epub 2007 Apr 22.


This paper describes the analysis of a novel modification identified on the light chain of a recombinant IgG2 antibody. This modification, a +162 Da adduct, suggestive of a single hexose addition, was observed by mass analysis of the reduced molecule. The modification was located on residue serine 66 of the light chain by investigation with LC-MS peptide mapping, mass spectrometry and N-terminal sequencing techniques. Location of the adduct on serine pointed the investigation toward O-linked glycosylation. Identification of the hexose residue was deduced from its elimination by action of alpha-mannosidase, providing evidence for the presence of an O-mannosylated light chain. This type of modification in the glycosylation profile of antibodies, to our knowledge, has not been reported for human IgG molecules.

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / chemistry*
  • Glycosylation
  • Humans
  • Immunoglobulin G / chemistry*
  • Mannose / chemistry*
  • Recombinant Proteins / chemistry*
  • Serine / chemistry
  • alpha-Mannosidase / metabolism


  • Antibodies, Monoclonal
  • Immunoglobulin G
  • Recombinant Proteins
  • Serine
  • alpha-Mannosidase
  • Mannose