title: Irradiation of GAPDH: a model for environmentally induced protein damage.
abstract: Environmental factors, including sunlight, are able to induce severe oxidative protein damage. The modified proteins are either repaired, degraded or escape from degradation and aggregate. In the present study we tested the effect of different sunlight components such as UV-A, UV-B, and infrared radiation on protein oxidation in vitro. We chose glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a model enzyme and analyzed the irradiation-induced enzyme activity loss, fragmentation and aggregation, and quantified various oxidative amino acid modifications. Since gamma-irradiation was used in numerous studies before, we used it for comparative purposes. Infrared radiation was unable to damage GAPDH in the dose range tested (0-1000 J/cm(2)). UV-A led to a decrease in free thiol content, which was connected with a loss in enzyme activity, while only at very high doses could moderate protein aggregation and fragmentation be observed. UV-B (0-2 J/cm(2)) and gamma-irradiation (0-500 Gy) led to a dose-dependent increase in protein modification. Interestingly, UV-B acted on specific amino acids, such as arginine, proline, and tyrosine, whereas gamma-irradiation acted more randomly. The possibility of using the amino acid oxidation pattern as a biomarker of the source of damage is discussed.
authors.affiliation: Research Institute for Environmental Medicine, Molecular Aging Research, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Voss
authors.forename: Hossein
authors.initials: H
authors.lastname: Hajimiragha
authors.forename: Martina
authors.initials: M
authors.lastname: Engels
authors.forename: Carsten
authors.initials: C
authors.lastname: Ruhwiedel
authors.forename: Christian
authors.initials: C
authors.lastname: Calles
authors.forename: Peter
authors.initials: P
authors.lastname: Schroeder
authors.forename: Tilman
authors.initials: T
authors.lastname: Grune
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D005720:Gamma Rays; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects*; D007259:Infrared Rays; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D050050:Protein Carbonylation; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D000596:Amino Acids; D013438:Sulfhydryl Compounds; D009243:NAD; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases