Allosteric inhibition of Dictyostelium discoideum fructose-1,6-bisphosphatase by fructose 2,6-bisphosphate.
It has been found that the inhibition of Dictyostelium discoideum fructose-1,6-bisphosphatase by fructose 2,6-P2 greatly diminished when the pH was raised to the range 8.5-9.5, which resulted in a marked decrease of the affinity for the inhibitor with no change in the Km for the substrate. This provides evidence for the involvement of an allosteric site for fructose 2,6-P2. Moreover, the fact that excess substrate inhibition also decreased at the pH values for minimal fructose 2,6-P2 inhibition, and was essentially abolished in the presence of fructose 2,6-P2, strongly suggests that this inhibition takes place by binding of fructose 1,6-P2 as a weak analogue of the physiological effector fructose 2,6-P2.
Andrés
V
V
Instituto de Investigaciones Biomédicas del CSIC, Departamento de Bioquímica de la Facultad de Medicina de la Universidad Autónoma, Madrid, Spain.
García-Salguero
L
L
Gómez
M E
ME
Aragón
J J
JJ
D000494:Allosteric Regulation; D004023:Dictyostelium / Q000201:enzymology*; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors*; D005635:Fructosediphosphates / Q000494:pharmacology*; D006598:Hexosediphosphates / Q000494:pharmacology*; D007700:Kinetics
D005635:Fructosediphosphates; D006598:Hexosediphosphates; C027652:fructose 2,6-diphosphate; D006597:Fructose-Bisphosphatase