title: Unexpected crosslinking and diglycation as advanced glycation end-products from glyoxal.
abstract: Glyoxal-derived advanced glycation end-products (AGEs) are formed in physiological systems affecting protein/peptide function and structure. These AGEs are generated during aging and chronic diseases such as diabetes and are considered arginine glycating agents. Thus, the study of glyoxal-derived AGEs in lysine residues and amino acid competition is addressed here using acetylated and non-acetylated undecapeptides, with one arginine and one lysine residue available for glycation. Tandem mass spectrometry results from a Fourier transform ion cyclotron resonance mass spectrometer showed glycated species at both the arginine and lysine residues. One species with the mass addition of 116.01096 Da is formed at the arginine residue. A possible structure is proposed to explain this finding (Nδ-[2-(dihydroxymethyl)-2H,3aH,4H,6aH-[1,3]dioxolo[5,6-d]imidazolin-5-yl]-L-ornithine-derived AGE). The second species corresponded to intramolecular crosslink involving the lysine residue and its presence is checked with ion-mobility mass spectrometry.
authors.affiliation: Warwick Centre for Analytical Science, Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Andrea F
authors.initials: AF
authors.lastname: Lopez-Clavijo
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Duque-Daza
authors.forename: Andrew
authors.initials: A
authors.lastname: Soulby
authors.forename: Isolda Romero
authors.initials: IR
authors.lastname: Canelon
authors.forename: Mark
authors.initials: M
authors.lastname: Barrow
authors.forename: Peter B
authors.initials: PB
authors.lastname: O'Connor
mesh_terms: D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry* / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000737:chemistry* / Q000378:metabolism; D006031:Glycosylation; D006037:Glyoxal / Q000737:chemistry* / Q000378:metabolism; D008239:Lysine / Q000737:chemistry; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D017127:Glycation End Products, Advanced; D010455:Peptides; D006037:Glyoxal; D008239:Lysine