And on top of that, these isoenzymes are usually controlled by different types of regulatory molecules. Now, one example of an isoenzyme found inside our body is lactate dehydrogenase LDH. And this is basically the molecule that is used in the process of anaerobic cellular respiration. So we have two types of isoenzymes for lactate dehydrogenase. One of them is found predominantly in the cardiac muscle cell and the other one is found in a skeletal muscle cell. And we'll discuss what their function is and what their difference is in more detail in the next several lectures.