Kinetic effects of fructose-1,6-bisphosphate on yeast phosphofructokinase.
Yeast phosphofructokinase is known to be effectively activated by fructose-2,6-bisphosphate and AMP. In the absence of the two effectors, fructose-1,6-bisphosphate activates or inhibits the enzyme according to the concentrations of the substrates and of inorganic phosphate. At cellular concentrations of the substrates, however, the effects of fructose-1,6-bisphosphate are negligible. Whereas the activation of the enzyme by AMP is not affected by fructose-1,6-bisphosphate, the latter was found to diminish strongly the activity of the fructose-2,6-bisphosphate-activated enzyme. Inorganic phosphate amplifies the activating effect of fructose-2,6-bisphosphate and augments also the deactivation of the fructose-2,6-bisphosphate-activated enzyme. The deactivating action of fructose-1,6-bisphosphate with respect to fructose-2,6-bisphosphate dominates at low concentrations of fructose-6-phosphate and high levels of ATP and might be of regulatory significance.
D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000494:pharmacology*; D006598:Hexosediphosphates / Q000494:pharmacology*; D007700:Kinetics; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D005635:Fructosediphosphates; D006598:Hexosediphosphates; D010732:Phosphofructokinase-1; C029063:fructose-1,6-diphosphate