Penzkofer, Alfons (2012) Reduction-Oxidation Photocycle Dynamics of Flavins in Starch Films. INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 13 (7). pp. 9157-9183. ISSN 1422-0067,
Full text not available from this repository. (Request a copy)Abstract
The blue-light photo-reduction (conversion of oxidized flavin quinone via flavin semiquinone to fully reduced flavin hydroquinone) and dark re-oxidation of the flavins riboflavin and lumiflavin in starch (alpha-amylose) films was studied by absorption and luminescence spectroscopy. Blue-light photo-excitation caused an absorption, fluorescence, and phosphorescence decrease which recovered in the dark. The photo-reduction dark-oxidation cycle could be repeated. The efficiency of photo-reduction decreased with exposed excitation energy, and the speed of re-oxidation in the dark slowed down with time after excitation. The absorption did not fully recover. The fluorescence efficiency after a long time of storage in the dark increased beyond the initial flavin quinone fluorescence efficiency. Flavin photo-excitation is thought to cause starch-flavin restructuring (static fluorescence quenching center formation), enabling enhanced photo-induced starch to flavin electron transfer with subsequent flavin reduction and starch oxidation. In the dark, after light switch-off, thermal reversion of flavin reduction and starch oxidation occurred.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | FLUORESCENCE SPECTROSCOPIC CHARACTERIZATION; BLUE-LIGHT PHOTORECEPTORS; TIME-RESOLVED FLUORESCENCE; NEG-M STRAIN; AQUEOUS-SOLUTION; CHLAMYDOMONAS-REINHARDTII; RHODOBACTER-SPHAEROIDES; ADENINE-DINUCLEOTIDE; EMISSION BEHAVIOR; ELECTRON-TRANSFER; riboflavin; lumiflavin; starch; oxystarch; flavin photo-reduction cycle; starch photo-oxidation cycle; static fluorescence quenching; photo-induced starch restructuring; phosphorescence; delayed fluorescence |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 11 May 2020 06:25 |
| Last Modified: | 11 May 2020 06:25 |
| URI: | https://pred.uni-regensburg.de/id/eprint/18472 |
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