ATP will bind onto a regulatory side of the isocitrate dehydrogenase enzyme. This will increase the affinity of the enzyme for the substrate isocytrade, which will increase the rate of the citric acid cycle. Now, conversely, what happens if we have plenty of ATP inside our cells so we have a high energy charge value and a cell doesn't want to actually use energy to produce these ATP molecules and so it wants to decrease the rate at which the citric acid cycle takes place. And now what happens? Instead of having allosteric activators, we have allosteric inhibitors that will bind onto isocitrate dehydrogenates and decrease its affinity for the isocitrate molecule. In fact, what will happen is the ATP molecules themselves will bind onto special region of ISOC citrate dehydrogenase and that will decrease the rate at which it will actually take place.