Baier, Juergen and Maisch, Tim and Maier, Max and Engel, Eva and Landthaler, Michael and Baeumler, Wolfgang (2006) Singlet oxygen generation by UVA light exposure of endogenous photosensitizers. BIOPHYSICAL JOURNAL, 91 (4). pp. 1452-1459. ISSN 0006-3495,
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UVA light (320 - 400 nm) has been shown to produce deleterious biological effects in tissue due to the generation of singlet oxygen by substances like flavins or urocanic acid. Riboflavin, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), beta-nicotinamide adenine dinucleotide (NAD), and beta-nicotinamide adenine dinucleotide phosphate (NADP), urocanic acid, or cholesterol in solution were excited at 355 nm. Singlet oxygen was directly detected by time-resolved measurement of its luminescence at 1270 nm. NAD, NADP, and cholesterol showed no luminescence signal possibly due to the very low absorption coefficient at 355 nm. Singlet oxygen luminescence of urocanic acid was clearly detected but the signal was too weak to quantify a quantum yield. The quantum yield of singlet oxygen was precisely determined for riboflavin (Phi(Delta) = 0.54 +/- 0.07), FMN (Phi(Delta) = 0.51 +/- 0.07), and FAD (Phi(Delta) = 0.07 +/- 0.02). In aerated solution, riboflavin and FMN generate more singlet oxygen than exogenous photosensitizers such as Photofrin, which are applied in photodynamic therapy to kill cancer cells. With decreasing oxygen concentration, the quantum yield of singlet oxygen generation decreased, which must be considered when assessing the role of singlet oxygen at low oxygen concentrations (inside tissue).
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MITOCHONDRIAL COMMON DELETION; QUANTUM YIELD; GENE-EXPRESSION; RATE CONSTANTS; UROCANIC ACID; RIBOFLAVIN; ACTIVATION; PHOTOOXIDATION; SENSITIZATION; DEGRADATION; |
| Subjects: | 500 Science > 530 Physics 500 Science > 540 Chemistry & allied sciences 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer Chemistry and Pharmacy > Institut für Organische Chemie > Lehrstuhl Prof. Dr. Burkhard König |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 03 Feb 2021 11:14 |
| Last Modified: | 03 Feb 2021 11:14 |
| URI: | https://pred.uni-regensburg.de/id/eprint/34164 |
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