Biological role of fibrinolysis.

Fibrinolysis is a basic defence mechanism of the organism designed to control the deposition of fibrin in the vascular system and elsewhere. When thrombin is generated by the coagulation system it acts on fibrinogen and 'precipitates' it out of solution as a polymer-fibrin. This polymer deposition is regulated by the fibrinolytic system which acts on the insoluble protein fibrin and, by splitting a limited number of peptide bonds, renders it soluble. This solubilisation mechanism which liquifies the fibrin clot is the fibrinolytic system. Fibrinolysis was first described in a rudimentary form over a century ago. Nowadays the term fibrinolysis is generally restricted to the 'fibrinolysing' action of the plasminogen-plasmin system, but fibrin is of course removed by other means such as phagocytosis and proteolysis by other enzymes.