| | 1 | Author
| M. Anfred Steingraber, Hanns Frohnm, Rüdiger Ham | Requires cookie* | | | Title
| Light-Dependent Sucrose Synthesis in Cell-Free (Reconstituted) Lysates of Evacuolated Mesophyll Protoplasts  | | | | Abstract
| Oat mesophyll protoplasts were evacuolated by centrifugation on a Percoll gradient and used as starting material for establishing a functional cell-free system. For this purpose evacuolated protoplasts were osm otically lysed. From the resulting homogenate a cytosolic fraction was obtained by silicon oil filtration. This fraction was used to dilute preparations o f lysed evacu olated protoplasts in order to reduce the number o f organelles per volume cytosol. The latter was necessary to increase light-dependent oxygen evolution o f the cell-free system. The result ing kind o f "reconstituted" system showed light-dependent sucrose formation (about 100 nmol (mg Chi)-1 • h r 1) with bicarbonate as the only substrate. As this property depends on a functional interaction o f chloroplast and cytosolic reactions, this cell-free system appeared to perform essential steps o f partitioning o f C 0 2 between starch and sucrose. Addition o f about 12 (im fructose 2 ,6 -bisphosphate, an inhibitor o f fructose 1,6 -bisphosphatase and an activator o f the PPi-dependent fructose 6 -phosphate phosphotransferase, caused sucrose degradation in the light. Thus, this cell-free system allows both the study o f cytosolic enzyme activities under quasi in vivo conditions and the manipulation o f cellular reaction sequences by plasma mem brane-impermeable compounds. | | | |
Reference
| Z. Naturforsch. 45c, 217 (1990); received January 11 1990 | | | |
Published
| 1990 | | | |
Keywords
| Avena sativa, Cell-Free System, Evacuolation, Mesophyll Protoplasts, Sucrose Synthesis | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/45/ZNC-1990-45c-0217.pdf | | | | Identifier
| ZNC-1990-45c-0217 | | | | Volume
| 45 | |
|
