plasminogen

n. substance in the blood which forms the enzyme plasmin (Biology)

Plasmin is an important enzyme  present in blood that degrades many blood plasma proteins, most notably fibrin clots. The degradation of fibrin is termed fibrinolysis.
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Plasminogen /plas·min·o·gen/ the inactive precursor of plasmin, occurring in plasma and converted to plasmin by the action of urokinase. [more]Plasminogen - Community and Resources

Noun
1. an inactive form of plasmin that occurs in plasma and is converted to plasmin by organic solvents
(hypernym) plasmin, fibrinolysin

n. plasminogen, substance in the blood which forms the enzyme plasmin (Biology)