This course is part of a series taught by Kevin Ahern at Oregon State University on General Biochemistry. For more information about online courses go to ecampus.oregonstate.edu 1. Zymogens are enzymes that are synthesized in an inactive form whose activation requires covalent modification, usually proteolytic cleavage. Examples include digestive enzymes, such as trypsin, chymotrypsin, elastase, and carboxypeptidase whose enzymatic activity might be harmful to the tissue where they are being made. 2. Trypsin is the primary activator of an entire class of proteolytic enzymes. Improper activation of trypsin in or close to the pancreas can lead to pancreatitis, which arises when the proteases attack proteins in the pancreas. 3. Activation of chymotrypsinogen to chymotrypsin, for example, requires trypsin. Trypsin makes an initial cleavage beween amino acids 15 and 16. A disulfide bond keeps the two pieces from coming completely apart, however. This creates an intermediately active form of chymotrypsin called pi-chymotrypsin. This form cleaves itself to remove two dipeptides and this results in full chymotrypsin activity. The three polypeptide pieces are held together by disulfide bonds. Note that three very minor changes in the chymotrypsinogen zymogen have converted a completely inactive enzyme to a fully active one. 4. Alpha-one-antitrypsin is an inhibitor of many proteases, including trypsin and elastase. Normally alpha-one-antitrypsin binds to elastase and prevents it <b>...</b>