title: "Internal residue loss": rearrangements occurring during the fragmentation of carbohydrates derivatized at the reducing terminus.
abstract: Rearrangement reactions involving migration of fucose and, occasionally, other residues have been found in the CID spectra of [M + H]+ and [M + 2H]2+ ions, but not [M + Na]+ ions, generated from several O-linked carbohydrates and milk sugars derivatized at their reducing termini with aromatic amines such as 2-aminobenzamide. Such rearrangements, which are similar to those reported by other investigators from several underivatized carbohydrates and glycosides, cause an apparent loss of sugar residues from within a carbohydrate chain and can produce ambiguous results during spectral interpretation. A mechanism, involving initial protonation of the amine nitrogen atom of the derivative, is proposed to account for the formation of the observed ions.
authors.affiliation: Oxford Glycobiology Institute, Department of Biochemistry, UK. dh@glycob.ox.ac.uk
authors.forename: David J
authors.initials: DJ
authors.lastname: Harvey
authors.forename: Taj S
authors.initials: TS
authors.lastname: Mattu
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wormald
authors.forename: Louise
authors.initials: L
authors.lastname: Royle
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Dwek
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Rudd
mesh_terms: D000588:Amines / Q000737:chemistry; D000818:Animals; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D005643:Fucose / Q000032:analysis; D008892:Milk / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000588:Amines; D002241:Carbohydrates; D005643:Fucose