The proteolytic enzymes have an essential function in all cells. Their activities are regulated by the rate of synthesis, activation of proenzymes and by the rate of synthesis of their inhibitors. They are synthesized in ribosomes like any other proteins and transported to various storage organelles or secreted from the cells and are activated in the pericellular space or in interstitium. Various cells and tissues have their characteristic enzyme patterns which serve their specific functions. Proteolytic enzymes take part and often have a regulatory role in numerous phases of cell function, e.g. cell division, migration, apoptotic as well as necrotic cell death etc. Diseases in which proteolysis has been subject of active research are e.g. cancer metastasis, viral infections, e.g. HIV, and Alzheimer's disease. They are also an essential part in any tissue remodelling, wound healing, throughout the kingdom of fauna and flora.