Answer:
Fructose 2,6-bisphosphate is a <em>positive</em> regulator of glycolysis and a <em>negative</em> regulator of gluconeogenesis.
Explanation:
Fructose-2,6-bisphophate is an allosteric effector of the enzymes phosphofructokinase-1, PFK-1 and fructose-1,6-bisphosphatase, FBPase-1.
When fructose-2,6-bisphosphate binds to its allosteric site on PFK-1, it increases the enzymes affinity for its substrate fructose-6- phosphate and reduces its affinity for ATP and citrate, its allosteric inhibitors. This favors favors glycolysis.
However, binding of fructose-2,6-bisphosphate on its allosteric site on FBpase-1 has the opposite effect on it. It reduces its affinity for its substrate, fructose-1,6-bisphosphate, thereby inibiting gluconeogenesis.
