title: Oxidative degradation of N(ε)-fructosylamine-substituted peptides in heated aqueous systems.
abstract: Glycation, or non-enzymatic glycosylation, is a common protein modification formed by reactions between reducing sugars (i.e. aldoses and ketoses) with protein amino groups. Resulting Amadori and Heyns compounds, respectively, can be oxidatively degraded yielding a structurally heterogeneous group of advanced glycation end-products. We have studied this process in aqueous conditions at 95 °C in terms of appearing products and their formation kinetics in the presence or absence of reactive oxygen species (ROS)-generating systems (iron(II) sulfate). RP-HPLC-ESI-MS revealed 20 products, 12 of which were confirmed after synthesis by identical retention times and fragmentation patterns. These products accumulated during the incubation period of 4 h (N(ε)-carboxymethyl-, N(ε)-formyl- and N(ε)-methyl lysine) or appeared intermediately (2-aminoadipic semialdehyde, N(ε)-ethanalyl lysine). Acidic and basic amino acid residues near the glycation site and elevated ROS levels in the reaction mixture had significant effects on both product formation and degradation kinetics.
authors.affiliation: Faculty of Chemistry and Mineralogy, Institute of Bioanalytical Chemistry, Universität Leipzig, Deutscher Platz 5, 04103, Leipzig, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Greifenhagen
authors.forename: Andrej
authors.initials: A
authors.lastname: Frolov
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
mesh_terms: D015074:2-Aminoadipic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005296:Ferrous Compounds / Q000737:chemistry; D005947:Glucose / Q000737:chemistry*; D017127:Glycation End Products, Advanced / Q000737:chemistry*; D006031:Glycosylation; D006358:Hot Temperature; D007700:Kinetics; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D014867:Water / Q000737:chemistry
chemical_list: D005296:Ferrous Compounds; D017127:Glycation End Products, Advanced; D010455:Peptides; D017382:Reactive Oxygen Species; D012996:Solutions; D014867:Water; D015074:2-Aminoadipic Acid; C020748:ferrous sulfate; C000061:allysine; D005947:Glucose