So the first reaction involves abstraction of a pair of high energy electrons to form the NADH. And this high energy intermediate known as oxalosuxnate and oxylosuxanate is unstable because it is a beto keto acid. So remember from organic chemistry that beta keto acids are generally unstable molecules. Now, the NADH that we produced will be used by the electron transport chain, as we'll discuss in a future lecture. So now let's move on to step two of this process that takes place in step three. So in the next step, we take that oxylosuxtonate and bivactivity of the same enzyme, isocitrate dehydrogenase.