And this isocitrate dehydrogenase will bind the isocitrate and the NAD plus more readily and that will increase the rate at which this reaction actually takes place. And that will increase the rate at which the overall citric acid cycle will actually take place. So when the cell needs to produce energy molecules, it has a low content of ATP. 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.