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Betreff: Biomarker re environmental oxidative protein damage....(GAPDH)...June 2007 |
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Von: JCMPelican @aol.com |
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Datum: Mon, 11 Jun 2007 18:32:40 EDT |
1:
Biol Chem. 2007 Jun;388(6):583-92.
Irradiation of GAPDH: a model for
environmentally induced protein damage.
Voss P, Hajimiragha H, Engels M, Ruhwiedel C, Calles C, Schroeder P, Grune T.
1Research
Institute for Environmental Medicine, Molecular Aging Research, Heinrich Heine
University Düsseldorf, D-40225 Düsseldorf, Germany.
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.
PMID: 17552905
[PubMed - in process] [ Emphasis
added....jcm...6-11-07....]