Enzyme
Enzymes can be regulated by being modified after their production. An example is the cleavage of the polypeptide chain. Chymotrypsin, a digestive protease, is produced in inactive form in the pancreas and transported in this form to the stomach where it is activated. This stops the enzyme from digesting the pancreas or other tissues before it enters the gut. This type of inactive precursor to an enzyme is known as a zymogen.