- Fibrinolytic enzymes are a group of proteolytic (protein-breaking) enzymes that play a critical role in the breakdown of fibrin, the insoluble protein that forms the structural framework of blood clots.
- These enzymes are part of the fibrinolytic system, which ensures that blood clots are removed once they have served their purpose, helping maintain normal blood flow and preventing complications such as thrombosis.
- The most well-known natural fibrinolytic enzyme in the human body is plasmin, which is produced from plasminogen, an inactive zymogen circulating in the blood. The activation of plasminogen to plasmin is primarily carried out by tissue plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). Once activated, plasmin digests fibrin into soluble fragments, effectively dissolving the clot.
- In addition to endogenous enzymes, microbial fibrinolytic enzymes have gained significant attention, especially for their potential use in thrombolytic therapy. Examples include:
- Streptokinase: Produced by Streptococcus species, it forms a complex with plasminogen to convert it into plasmin.
- Staphylokinase: Produced by Staphylococcus aureus, with a similar function to streptokinase.
- Nattokinase: A potent fibrinolytic enzyme derived from Bacillus subtilis during the fermentation of soybeans (natto), known for its oral bioavailability and thrombolytic potential.
- Lumbrokinase: Derived from earthworms, also shows strong fibrinolytic activity and is used in some alternative therapies for cardiovascular conditions.
- Fibrinolytic enzymes are used clinically in the treatment of acute myocardial infarction, pulmonary embolism, and ischemic stroke, where rapid clot dissolution is necessary to restore blood flow. Research is ongoing to discover and optimize new fibrinolytic enzymes, especially from microbial and natural sources, due to their cost-effectiveness and potential for fewer side effects compared to conventional drugs.
