And what the cell does is to make sure the rate is high is it stimulates the isocitrate dehydrogenase. So the isocitrate dehydrogenase, being an allosteric enzyme, contains allosteric regulatory sites and an allosteric activator molecule, ADP adenosine diphostate, will go on and bind onto special location on the enzyme isocitrate dehydrogenase. And once it binds, it increases its affinity for the substrate molecule isocitrate. 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.