The involvement of fructose 2,6-bisphosphate in substrate cycle control in the nonoxidative stage of the pentose phosphate pathway. A phosphorus magnetic resonance spectroscopy study
Belyaeva, N.F.; Golubev, M.A.; Grigorovich, J.A.; Dubinsky, Z.V.; Semenova, N.A.; Pitkänen, E.; Korovkin, B.F.
Experientia 50(8): 780-784
1994
ISSN/ISBN: 0014-4754 PMID: 8070536 Document Number: 431099
The role of fructose 2,6-bisphosphate in the interconversion of sedoheptulose 7-phosphate and sedoheptulose 1,7-bisphosphate in rat liver cytosol fractions was studied by means of phosphorus magnetic resonance spectroscopy. When the activity of 6-phosphofructo-1-kinase was inhibited by a high concentration of ATP, the addition of fructose 2,6-bisphosphate led to a marked decrease in sedoheptulose 7-phosphate levels, accompanied by an increased concentration of ADP. Fructose 2,6-bisphosphate essentially inhibited both the decrease in sedoheptulose 1,7-bisphosphate concentration and the accumulation of P-i in the incubation mixture. The data provided evidence that fructose 2,6-bisphosphate can regulate the substrate cycle: sedoheptulose 7-phosphate dblarw sedoheptulose 1,7-bisphosphate in the liver, and thus control the flux through the nonoxidative stage of the pentose phosphate pathway.