Regulation of Enzyme Activities by Free Mg〔2+〕 Concentration--Regulation of Stromal Fructose-1,6-bisphosphatase and Ribulose 1,5-Bisphosphate Carboxylase Activities (糖質関連酵素化学シンポジウム) Regulation of Enzyme Activities by Free Mg^<2+> Concentration : Regulation of Stromal Fructose-1, 6-bisphosphatase and Ribulose 1, 5-Bisphosphate Carboxylase Activities
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Although Mg is abundant within the cell, most is chelated to various organic molecules; only a small fraction of intracellular Mg is in the free (ionized) form, Mgtt Free Mg<SUP>2+</SUP> regulates manyenzyme activities in cells. The effect of free Mg<SUP>2+</SUP> concentration on the activities of spinach hloroplast fructose-1, 6-bisphosphatase (FBPase) and ribulose 1, 5-bisphosphate carboxylase (rubisco) was examined. Free Mg<SUP>2+</SUP> concentrations in the assay mixtures were directly measured by a Mgtsensitive dye, mag-fura-2. FBPase was activated by a physiological concentration range of free Mgt, but the activation of rubisco was not observed. These results suggest that in illuminated chloroplasts, the increase in free Mg<SUP>2+</SUP> activates FBPase, and this may be a physiological factor to stimulate CO<SUB>2</SUB> fixation.
- Journal of Applied Glycoscience
Journal of Applied Glycoscience 49(2), 199-203, 2002-04-01
The Japanese Society of Applied Glycoscience