Plasmin is an important factor in fibrinolysis, the breakdown of fibrin polymers formed during blood clotting.

Produced mainly in the liver, plasminogen is the inactive zymogen form of plasmin, and circulates in plasma in a closed conformation that cannot be activated.

Factor XI (FXI) is a serine protase produced by the liver and circulates in its inactive form.

Reteplase and tenecteplase both received FDA approval after alteplase, and have nonidentical structures to tPA.

[1] These recombinant forms of tPA have been shown to have a longer half-life in the blood and greater resistance to inhibition, resulting in an increased capacity to treat thrombolytic diseases.

MMP activation contributes to tumor cell invasion and metastasis by degradation of ECM components.