Sensitive Liquid Chromatography-Electrospray Mass Spectrometry Allows for the Analysis of the O-Glycosylation of Immunoprecipitated Proteins from Cells or Tissues: Application to MUC1 Glycosylation in Cancer

We have analyzed the structures of the glycans on immunoprecipitated proteins from small amounts of cell or tissue lysates, by liquid-chromatography electrospray mass spectrometry (LC-ESI-MS) and MS/MS. The sensitive and specific method was applied to the analysis of the O-glycosylation of MUC1 in breast, prostate and gastric cancer, including analysis of a patient tumor specimen. The method will be applicable for the glycosylation analysis of individual proteins.