(1) The cytoplasm contains numerous glycogen granules; however, zymogen and neurosecretory granules are absent.(2) The proteases are secreted in forms of zymogen (ie, inactive precursor to enzyme), such as trypsinogen, chymotrypsinogen, and procarboxypeptidase.(3) One of the key reactions in the mammalian blood coagulation and hemostatic process is the cleavage of the zymogen prothrombin to thrombin which in turn activates fibrinogen to fibrin, eventually resulting in clot formation.(4) How this process occurs is unclear; however, it is believed that something activates the zymogens while they are still in the pancreas.(5) Still other proteins (of the enzyme class) are synthesized as inactive precursors called zymogens .
