ENZYMES can be used in therapeutics, though in general there are difficulties in delivering them to their proposed sites of action. There are commonly serious side-effects, normally immune reactions. There have been repeated attempts to use proteolytic enzymes in therapeutics to supplement deficiencies within the gastrointestinal tract, and necessarily there are difficulties in administering such enzymes without erosion of the mouth and upper digestive tract. Some notes follow on enzymes currently used.

Anistreplase is a plasminogen streptokinase activator used as a fibrinolytic agent in the treatment of acute myocardial infarction. Crisantaspase (asparaginase) is an enzyme isolated from E. coli, which is thought to have some activity as an anticancer and antileukaemic agent. Batroxobin from snake venom is a serine protease and with its thrombin-like enzyme it is a haemostatic and defibrinogenating agent, and can be used in peripheral arterial circulatory disorders. Cellulase is a concentrate of cellulose-splitting (cellulytic) enzymes isolated from Aspergillus niger. It can be given by mouth, in combination with other digestive enzymes, to aid digestion. Chymopapain is a proteolytic enzyme isolated from Carica papaya, and can be used in the form of injections into vertebral discs in treating sciatica and lumbar pain (herniated lumbar discs). Chymotrypsin is a proteolytic enzyme that can be used by injection to dissolve a suspensory ligament of the lens of the eye to aid surgical removal of the lens because of cataract. Hyalosidase (a highly purified form of hyaluronidase) is a hyaluronoglucosidase that has been used as a fibrinolytic enzyme for the treatment of myocardial infarction.

Hyaluronidase contains enzymes that depolymerize hyaluronic acid, and is used by injection in the treatment of subcutaneous and intravenous extravasation injuries, to increase the permeability of soft tissues to injected drugs, and as an ophthalmological agent. Pancreatin, isolated from pancreas of pig and cow, is a digestive enzyme with protease and amylase activity, and is used in replacement therapy (for instance, in cystic fibrosis, and also used by mouth in the form of capsules or granules following operations involving removal of pancreatic tissue, such as panreatectomy and gastrectomy). Papain is a vegetable pepsin, a purified proteolytic substance derived from Carica papaya, and as a proteolytic enzyme it is used topically to prevent adhesions, taken by mouth as a protein digestant, and as an anthelmintic. Rizolipase is a concentrate of pancreatic enzymes standardized for lipase content, used by mouth as a digestive enzyme. Saruplase is a recombinant human single-chain urokinase-type plasminogen activator under development as a thrombolytic agent (see fibrinolytic agents). Streptokinase is isolated from Streptococcus haemolyticus and is used as a fibrinolytic agent in the treatment of myocardial infarction and deep-vein thrombosis. Sutilains is derived from Bacillus subtilis and contains proteolytic enzymes used for debridement of wound and burns, in moist conditions by topical application. Trypsin is a proteolytic enzyme extracted from bovine pancreatic gland that has been used topically for the debridement of wound and burns. It is also used combined with chymotrypsin, and taken by mouth for digestive insufficiency. It has also been inhaled into the lungs to liquefy viscous sputum. Urokinase is a proteolytic enzyme (physiologically present in mammalian blood) which activates plasminogen to plasmin. It is used by infusion as a fibrinolytic agent to treat pulmonary embolism and myocardial infarction.