title: Ethyl Esterification for MALDI-MS Analysis of Protein Glycosylation.
abstract: Ethyl esterification is a technique for the chemical modification of sialylated glycans, leading to enhanced stability when performing matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS), as well as allowing the efficient detection of both sialylated and non-sialylated glycans in positive ion mode. In addition, the method shows specific reaction products for α2,3- and α2,6-linked sialic acids, leading to an MS distinguishable mass difference. Here, we describe the ethyl esterification protocol for 96 glycan samples, including enzymatic N-glycan release, the aforementioned ethyl esterification, glycan enrichment, MALDI target preparation, and the MS(/MS) measurement.
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Karli R
authors.initials: KR
authors.lastname: Reiding
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Lonardi
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Agnes L
authors.initials: AL
authors.lastname: Hipgrave Ederveen
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands. m.wuhrer@lumc.nl.|Division of BioAnalytical Chemistry, VU University Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands. m.wuhrer@lumc.nl.
authors.forename: Manfred
authors.initials: M
authors.lastname: Wuhrer
mesh_terms: D004951:Esterification; D006023:Glycoproteins / Q000737:chemistry*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D006023:Glycoproteins; D011506:Proteins; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
keywords: Cotton; Ethyl esterification (EE); Hydrophilic interaction liquid chromatography (HILIC); Linkage-specific; Mass spectrometry (MS); Matrix-assisted laser desorption/ionization (MALDI); N-glycan release; Peptide-N-glycosidase F (PNGase F); Sepharose; Sialic acid (N-acetylneuraminic acid); Solid-phase extraction (SPE); Stabilization