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. And some examples include digestive enzymes, for example, chimotrypsin, we have blood clotting enzymes. Fibrin, we have hormones, for example, adrenal, corticotropic hormone, ACTH. All these different types of hormones in our body are synthesized initially in their inactive state and to activate them, some type of enzyme, some type of catalyst basically cleaves a peptide bond.