Allosteric inhibition of Dictyostelium discoideum fructose‐1,6‐bisphosphatase by fructose 2,6‐bisphosphate

摘要

>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 K_m 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.