Now many of the digestive enzymes in the stomach as well as in a small intestine undergo this process of proteolysis. Now, let's move on to the fifth type of posttranslational modification, known as nacetythylation. So, nacetylation is the transfer of an acetyl group from one molecule to an amino acid, or unto the polypeptide chain. Now, this process not only takes place after our translation took place, but it also actually takes place during the process of translation. So in most eukaryotic cells, when translation is still actually taking place, the first amino acid in the growing polypeptide chain, usually our methionine amino acid, is removed and replaced by our acetyl group. And this process is known as an acetylation.