title: Identification of N-linked oligosaccharides of rat insulin-like growth factor binding protein-4.
abstract: Insulin-like growth factor binding protein-4 (IGFBP-4) is, like the other five IGFBPs, a critical regulator of the activity of insulin-like growth factor (IGF)-I and IGF-II. Whereas IGFBP-1 and IGFBP-2 are not glycosylated, IGFBP-3 and IGFBP-4 are N-glycosylated and IGFBP-5 and IGFBP-6 are O-glycosylated. In this study we identified the glycosylation of IGFBP-4 using a nanoflow LC/MS/MS techniques. Although N-linked oligosaccharides are structurally diverse, their variants are well reported in the literature. Based on the molecular weight of the possible oligosaccharide moieties, we identified five different glycosylation isoforms of the protein. Identified glycans were biantennary and differ in the number of sialic acid terminal residues and/or core modification with fucose.
authors.affiliation: Thermo Finnigan, Proteomics Division, 355 River Oaks Parkway, San Jose, CA 95134, USA. dchelius@thermofinnigan.com
authors.forename: Dirk
authors.initials: D
authors.lastname: Chelius
authors.forename: Shiaw-Lin
authors.initials: SL
authors.lastname: Wu
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Bondarenko
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002240:Carbohydrate Sequence; D006031:Glycosylation; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000097:blood / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D051381:Rats; D014357:Trypsin
chemical_list: D018974:Insulin-Like Growth Factor Binding Protein 4; D009844:Oligosaccharides; D010446:Peptide Fragments; D014357:Trypsin