By inhibiting the activity of these two enzymes, we have isocytrate dehydrogenase, step three and alpha key to gluterate dehydrogenase. Now, in the case of inhibiting enzyme four of step four, we essentially increase the build up of the alpha ketoglutrate. And when we increase the concentration of alpha ketoglutrate, we can actually use the access alpha ketoglutrate to produce specific types of amino acids, as we'll discuss in the future lecture. In fact, we can also produce specific types of purine nitrogenous bases. So we see that the citric acid cycle is in fact regulated very closely by our cells. So we have these three different places where we can regulate the citric acid cycle.