Granzhan, A. and Penzkofer, Alfons and Hauska, Günter (2004) Photo-degradation of bacteriochlorophyll c in intact cells and extracts from Chlorobium tepidum. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 165 (1-3). pp. 75-89. ISSN 1010-6030,
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The photo-stability of bacteriochlorophyll c (Bchlc) in an acetone-methanol-water solution extracted from Chlorobium tepidum and in the chlorosomes of intact Chlorobium tepidum cells is studied. The photo-stability of Bchlc in the chlorosomes is high (quantum yield of photo-degradation phi(D) 8 X 10(-7)). In air-saturated acetone-methanol-water solution the photo-degradation of Bchlc is caused by chemical reaction with the dissolved oxygen, where triplet Bchlc produces singlet oxygen, and singlet oxygen reacts with Bchlc to form stable oxidized linear tetrapyrroles as well as intermediate oxidized bacteriochlorophylls. The intermediate photoproducts degrade to linear tetrapyrroles by the catalytic action of triplet oxygen. The initial quantum yield of photo-degradation is direct proportional to the concentration of Bchlc giving phi(D,O) approximate to 0.011 for a 7 x 10(-6) M solution at an excitation wavelength of 672 nm. In nitrogen-bubbled solution the photo-degradation is dominated by direct photoproduct formation in the triplet state of Bchlc. Long-wavelength absorbing intermediate photoproducts degrade slowly in the dark to short-wavelength absorbing stable photoproducts. The quantum yield of photo-degradation of a de-oxygenated solution was found to be phi(D,0) approximate to 0.0012 for excitation at 672 nm. (C) 2004 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GREEN-SULFUR BACTERIUM; COMPLETE GENOME SEQUENCE; CHLOROFLEXUS-AURANTIACUS; ENERGY-TRANSFER; PHOTOSYNTHETIC BACTERIA; EXCITON DYNAMICS; SINGLET OXYGEN; BCHL-C; CHLOROSOMES; DERIVATIVES; bacteriochlorophyll c; Chlorobium tepidum; photo-degradation; photo-oxidation |
| Subjects: | 500 Science > 530 Physics 500 Science > 580 Botanical sciences |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer Biology, Preclinical Medicine > Institut für Pflanzenwissenschaften > Alumni or Retired > Prof. Dr. Günter Hauska |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 07 Jul 2021 05:35 |
| Last Modified: | 07 Jul 2021 05:35 |
| URI: | https://pred.uni-regensburg.de/id/eprint/37438 |
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