Fructose-2,6-bisphosphate and control of carbohydrate metabolism in eukaryotes.
Fructose-2,6-bisphosphate is an important intracellular biofactor in the control of carbohydrate metabolic fluxes in eukaryotes. It is generated from ATP and fructose-6-phosphate by 6-phosphofructo-2-kinase and degraded to fructose-6-phosphate and phosphate ion by fructose-2,6-bisphosphatase. In most organisms these enzymatic activities are contained in a single polypeptide. The reciprocal modulation of the kinase and bisphosphatase activities by post-translational modifications places the level of the biofactor under the control of extra-cellular signals. In general, these signals are generated in response to changing nutritional states, therefore, fructose-2,6-bisphosphate plays a role in the adaptation of organisms, and the tissues within them, to changes in environmental and metabolic states. Although the specific mechanism of fructose-2,6-bisphosphate action varies between species and between tissues, most involve the allosteric activation of 6-phosphofructo-1-kinase and inhibition of fructose-1,6-bisphosphatase. These highly conserved enzymes regulate the fructose-6-phosphate/fructose-1,6-bisphosphate cycle, and thereby, determine the carbon flux. It is by reciprocal modulation of these activities that fructose-2,6-bisphosphate plays a fundamental role in eukaryotic carbohydrate metabolism.
Okar
D A
DA
University of Minnesota, Medical School, Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis 55455, USA.
Lange
A J
AJ
D000818:Animals; D050260:Carbohydrate Metabolism; D005057:Eukaryotic Cells / Q000378:metabolism; D005635:Fructosediphosphates / Q000378:metabolism*; D006706:Homeostasis; D010732:Phosphofructokinase-1 / Q000378:metabolism; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010944:Plants / Q000378:metabolism
D005635:Fructosediphosphates; C027652:fructose 2,6-diphosphate; D025481:Phosphofructokinase-2; D010732:Phosphofructokinase-1; D010744:Phosphoric Monoester Hydrolases