Biochem/physiol Actions

Plasminogen is the inactive precursor of the protease plasmin. Plasminogen is activated by the action of either tissue plasminogen activator (tPA), which primarily activates the fibrinolytic (thrombolytic) activity of plasmin, or urokinase plasminogen activator (uPA), which is associated with extracellular matrix remodeling and cell migration. Plasmin cleaves fibrin/fibrinogen and blood coagulation factors V/Va and VIII/VIIIa. It activates matrix metalloproteinases by cleaving the inactive proenzymes. It is also involved in the activation of some growth factors, such as vascular endothelial growth factor (VEGF) and transforming growth factor β (TGF-β).

The activated form of plasminogen, plasmin, was shown to promote the migration of melanoma and lung tumor cells plated on the extracellular matrix protein laminin by altering protein kinase C signaling.

Other Notes

ε-Aminocaproic acid free

Physical form

Lyophilized powder containing NaCl, EDTA, lysine, and Tris buffer salts

Reconstitution

Solutions should be stored in buffer containing 20 mM lysine at neutral pH. The protein should be as concentrated as possible. Frozen in aliquots at −20 °C, it should be stable for several weeks.

Unit Definition

One unit will produce a δA₂₇₅ of 1.0 from α-casein in 20 min at pH 7.5 at 37 °C, when measuring perchloric acid soluble products in a volume of 5.0 mL. Activity determined after activation to plasmin with urokinase.