| | 1 | Author
| Gottfried Martin, Peter Böger | Requires cookie* | | | Title
| Two Ways of Hydrogen Peroxide Formation in the Oxidative Inactivation of Cyanobacterial Glutamine Synthetase  | | | | Abstract
| Using crude extracts from the cyanobacterium Anabaena variabilis glutamine synthetase (GS) activity was rapidly irreversibly reduced to about 60% during dark incubation ("sponta neous GS inactivation"). An additional decrease was observed by the addition of ammonia in the light ("ammonia-m ediated inactivation"). Both effects were prevented by EDTA, MnCl2 or catalase indicative of the involvement of H 20 2. This is a key interm ediate in oxida tive enzyme inactivation. In both spontaneous and am monia-mediated GS inactivation H 20 2 is produced in different ways. Spontaneous inactivation is prevented by depletion of reduced pyridine nucleotides which apparently donate electrons to produce H 20 2. Fractionation of the crude extract showed that the light-enhanced GS inactivation by ammonia required the presence of thylakoid membranes. The photosynthesis inhibitor DCM U decreased GS inacti vation by ammonia. For the inactivation in the light apparently H 20 2 is produced from super oxide during photosynthetic electron transport. | | | |
Reference
| Z. Naturforsch. 52c, 812—816 (1997); received August 12 1997 | | | |
Published
| 1997 | | | |
Keywords
| Glutamine Synthetase, Protein Oxidation Ammonia Effect, Photosynthetic Hydrogen Peroxide Production, Cyanobacterium, Anabaena variabilis | | | |
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| default:Reihe_C/52/ZNC-1997-52c-0812.pdf | | | | Identifier
| ZNC-1997-52c-0812 | | | | Volume
| 52 | |
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