title: Regulation of fructose 2,6-bisphosphate concentration in spinach leaves.
abstract: Fructose-6-phosphate 2-kinase and fructose-2,6-bisphosphatase have been partially purified from spinach leaves and their regulatory properties studied. Fructose-6-phosphate 2-kinase was activated by phosphate and fructose 6-phosphate, and inhibited by 3-phosphoglycerate and dihydroxyacetone phosphate. Fructose-2,6-bisphosphatase was inhibited by fructose 6-phosphate and phosphate. The interaction between these effectors was studied when they were varied, alone or in combination, over a range of concentrations representative of those in the cytosol of spinach leaf cells. In conditions when dihydroxyacetone phosphate or 3-phosphoglycerate rise, as is typical during photosynthesis, the fructose 2,6-bisphosphate level will decrease, which will favour sucrose synthesis. In conditions when fructose 6-phosphate accumulates, fructose 2,6-bisphosphate should rise, which will favour a restriction of sucrose synthesis and promotion of starch synthesis.
mesh_terms: D003600:Cytosol / Q000378:metabolism; D004099:Dihydroxyacetone Phosphate / Q000378:metabolism; D005635:Fructosediphosphates / Q000378:metabolism*; D005636:Fructosephosphates / Q000378:metabolism; D005988:Glyceric Acids / Q000378:metabolism; D006598:Hexosediphosphates / Q000378:metabolism*; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010944:Plants / Q000378:metabolism*
chemical_list: D005635:Fructosediphosphates; D005636:Fructosephosphates; D005988:Glyceric Acids; D006598:Hexosediphosphates; D010710:Phosphates; D004099:Dihydroxyacetone Phosphate; C027618:fructose-6-phosphate; C027652:fructose 2,6-diphosphate; C005156:3-phosphoglycerate; D010770:Phosphotransferases; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases