Influence of inorganic phosphate on the kinetic properties of yeast phosphofructokinase.

Yeast phosphofructokinase is effectively activated by inorganic phosphate. In the absence of other allosteric stimulators, inorganic phosphate increases the maximum activity of the enzyme only. In the presence of the activators AMP and fructose 2,6-bisphosphate inorganic phosphate causes changes in the maximum activity and the enzyme affinity to fructose 6-phosphate. Inorganic phosphate augments the sensitivity of phosphofructokinase to the activators AMP and fructose 2,6-bisphosphate and increases the respective maximum activities. The extent of activation of the enzyme by inorganic phosphate prevails at low levels of fructose 6-phosphate and high ATP concentrations.