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.
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 Pi in the incubation mixture. The data provided evidence that fructose 2,6-bisphosphate can regulate the substrate cycle: sedoheptulose 7-phosphate<-->sedoheptulose 1,7-bisphosphate in the liver, and thus control the flux through the nonoxidative stage of the pentose phosphate pathway.
Belyaeva
N F
NF
Institute of Biological and Medical Chemistry RAMS, Moscow, Russia.
Golubev
M A
MA
Grigorovich
J A
JA
Dubinsky
Z V
ZV
Semenova
N A
NA
Pitkänen
E
E
Korovkin
B F
BF
D000818:Animals; D003600:Cytosol / Q000378:metabolism; D005635:Fructosediphosphates / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008954:Models, Biological; D010427:Pentose Phosphate Pathway; D010758:Phosphorus; D051381:Rats; D017208:Rats, Wistar; D013403:Sugar Phosphates / Q000378:metabolism; D013997:Time Factors
D005635:Fructosediphosphates; D013403:Sugar Phosphates; C020495:sedoheptulose 7-phosphate; D010758:Phosphorus; C027652:fructose 2,6-diphosphate