[Allosteric regulation in the open futile cycle fructose-6-P--fructose-1,6-P2].

The effect of fructosebisphosphatase inhibition and phosphofructokinase activation by fructose-1,6-bisphosphate on a parasite recirculation of substrates in the futile (energy-dissipating) cycle fructose-6-P in equilibrium fructose-1,6-P2 has been studied. Both the inhibition and activation have been shown to produce self-oscillations in the cycle under flow-through conditions. The common recirculation with both regulatory mechanisms present is about half as high as with only one of them. The analysis fulfilled resulted in a conclusion of the importance of the concerted action of substrate inhibition and product activation both in the cycle fructose-6-P in equilibrium fructose-1,6-P2 and in the cycles glutamine in equilibrium glutamate and acetyl-CoA in equilibrium fatty acids playing an important part in the amino acid and lipid metabolism regulation.