Plasminogeno

Plasminogeno is a glycoprotein present in human plasma that serves as the inactive precursor of plasmin, the enzyme responsible for breaking down fibrin clots. It is synthesized primarily in the liver and released into the bloodstream where it circulates bound to alpha‑2‑antiplasmin. Activation occurs through proteolytic cleavage by tissue plasminogen activator (tPA) and urokinase‑type plasminogen activator (uPA), converting plasminogeno into active plasmin. Once released, plasmin degrades fibrin strands and also cleaves other coagulation proteins, thereby regulating the fibrinolytic system.

The molecular weight of plasminogeno is approximately 78 kDa, and its structure consists of five kringle domains followed by a serine protease domain. These domains are key for substrate recognition and inhibitor binding. Plasminogeno levels are governed by hepatic synthesis and are modulated by hormones, cytokines, and inflammatory mediators. In a healthy individual, normal plasma concentrations range from 200 to 300 μg/mL, though reference ranges may vary among laboratories.

Clinical significance includes congenital plasminogen deficiency, a rare autosomal recessive disorder that predisposes individuals to impaired fibrinolysis, recurrent venous thrombosis, and, in some cases, a distinctive bleeding disorder. Elevated plasminogeno levels are observed in inflammatory conditions, liver disease, and certain cancers, reflecting altered fibrinolytic activity. Measurement of plasminogeno activity is employed in diagnostic assays for thrombosis risk assessment and for monitoring fibrinolytic therapy in clinical settings.