On the role of chloroplastic phosphoglucomutase in the regulation of starch turnover |
| |
Authors: | Andrea Hattenbach Dieter Heineke |
| |
Institution: | Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung Biochemie der Pflanze, Untere Karspüle 2, D-37073 G?ttingen Germany, DE
|
| |
Abstract: | When spinach (Spinacia oleracea L.) leaf disks were incubated in 10% polyethylene glycol to induce water stress, the ratio of glucose-1-phosphate to glucose-6-phosphate
increased. This increase indicated an imbalance in the phosphoglucomutase (EC 2.7.5.1) reaction, which was earlier observed
to be close to equilibrium, and was accompanied by higher fructose-1,6-bisphosphate and ribulose-1,5-bisphosphate concentrations.
Because starch degradation was assumed to be the source of the glucose-1-phosphate accumulation, the kinetic properties of
plastidic phosphoglucomutase were analysed. It was found that physiological concentrations of both sugar bisphosphates inhibited
phosphoglucomutase by about 50%. From this observation it was concluded that under conditions in which fructose-1,6-bisphosphate
and ribulose-1,5-bisphosphate accumulated, an inhibition of phosphoglucomutase activity restricted the carbon exchange between
the Calvin cycle and starch turnover.
Received: 23 March 1998 / Accepted: 26 August 1998 |
| |
Keywords: | : Plastidic phosphoglucomutase Spinacia Starch turnover |
本文献已被 SpringerLink 等数据库收录! |
|