Evidence for a cytosolic-dependent light induction of chloroplastic glutamine synthetase during greening of etiolated rice leaves
✍ Scribed by Bertrand Hirel; Jean Vidal; Pierre Gadal
- Publisher
- Springer-Verlag
- Year
- 1982
- Tongue
- English
- Weight
- 675 KB
- Volume
- 155
- Category
- Article
- ISSN
- 0032-0935
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✦ Synopsis
During the greening of etiolated rice leaves, total glutamine synthetase activity increases about twofold, and after 48 h the level of activity usually observed in green leaves is obtained. A density-labeling experiment with deuterium demonstrates that the increase in enzyme activity is due to a synthesis of the enzyme. The enhanced activity obtained upon greening is the result of two different phenomena: there is a fivefold increase of chloroplastic glutamine synthetase content accompanied by a concommitant decrease (twofold) of the cytosolic glutamine synthetase. The increase ofchloroplastic glutamine synthetase (GSz) is only inhibited by cycloheximide and not by lincomycin. This result indicates a cytosolic synthesis of GS2. The synthesis of GS2 was confirmed by a quantification of the protein by an immunochemical method. It was demonstrated that GS2 protein content in green leaves is fivefold higher than in etiolated leaves.