Comprehensive Analysis of Recombinant Human Erythropoietin Glycoforms by Capillary Electrophoresis and Nanoflow Liquid Chromatography Coupled with Middle-down Mass Spectrometry

摘要

CESI-MS technique is reproducible (RSD <10%) and sensitive, obtaining the same sequence coverage and number of glycopeptides with five times lower amount of sample than for nLC-MS experiments. CESI separation of glycoforms is clearly based on differences in the number of sialic acid residues (that is, difference in charge) and the peptide to glycan mass ratios. In the present study, we used neutral or bare fused silica capillaries which demonstrated high adsorption for glycopeptides with high glycan to peptide ratios. New MS compatible coatings with moderate to low reversed electroosmotic flow would be highly desirable.