For example, epinephrine, a hormone, and a newer transmitter can act on the serene and three anion amino acids by phosphorylating them. And that can turn on or off many different types of molecules and reactions of processes that exist inside our body. For example, insulin, which is a molecule that is used to regulate the amount of glucose found inside our body, inside our blood functions via this process. So we can turn on or off insulin by using these phosphoryl groups. Now, finally, we can also not only modify the amino acids, but in some cases when we cleave peptides within the proteins, within our polypeptide that can activate or deactivate our protein. So many, many proteins inside our body are actually synthesized in their inactive form.