Plasmin is an enzyme produced in the body for the primary purpose of breaking down fibrin, a key component in blood clots. This enzyme acts as an anticoagulant and clot disperser inside the body. It is part of a large family of proteins and enzymes that respond to injuries in a cascading series of reactions that begins when an injury occurs and ends when the healing process is complete. Numerous labs manufacture these compounds for use in scientific research, including components from both human and animal sources.
The body needs a steady supply of plasmin to respond to ongoing needs, but having it activated and moving throughout the body can result in problems. It addresses this issue by making an inactive precursor known as plasminogen. Plasminogen is produced in the liver and it circulates freely. When a need for plasmin occurs, chemicals that cleave the plasminogen to activate it by turning it into plasmin are released.
This enzyme is known as a proteolytic enzyme because it breaks down proteins. In addition to breaking down fibrin, it can also act on fibrinogen, the precursor to fibrin, and several other proteins found in the body. Plasmin could be thought of as the enzyme that comes along for cleanup once a clot is no longer necessary. If clots were left in place, they would grow and could eventually break off, a very undesirable state of affairs. Plasmin dismantles the fibrin so that the clot can break up and be expelled from the body safely.
Once a clot is broken apart into its components, the body can expel unneeded parts as waste products and recycle the others for production of other proteins and enzymes. This process is continually occurring, generating a steady supply of materials to respond to new injuries and other needs. These processes are regulated by a number of genes that code for the production of specific proteins, enzymes, and other compounds in the body.
As a clot buster, plasmin has therapeutic applications. Patients who are not producing enough of the enzyme, or who have a clotting problem, can be given infusions of plasmin to break up their clots safely. Other anticoagulant medications can be used for this purpose, as well in patients with thickened blood, excessive clotting, and related medical issues. These medications need to be administered carefully because an excess can be dangerous. Too many anticoagulants may prevent a patient's blood from clotting when it needs to, leading to hemorrhage.