The next question is the next topic we're going to basically study is enzyme regulation. So how exactly do the cells inside our body actually monitor, regulate and control the activity and the functionality of all the different types of enzymes? So, as we'll discuss in this lecture, there are five major mechanisms of control. One is called allosteric control. And we actually spoke about this in detail when we discussed the hemoglobin molecule. The second type of mechanism of regulation is reversible covalent modification.