And these proteins usually act as receptors for other important biological molecules such as, for example, neurotransmitters. Now let's move on to the fourth type of post translational modification process known as proteolysis. So proteollysis is basically the process by which certain types of enzymes known as proteases actually cut our proteins. Now why would we want to cut a protein? Well, basically certain proteins are synthesized in their inactive or xiaomogen form. In order to actually activate those proteins, our enzymes called proteases must break certain peptide bonds in those proteins.