Cleavage of the serine proteinase plasminogen to form plasmin is the central event in the dissolution of blood clots by the fibrinolytic system. Within the fibrinolytic cascade, the serine proteinases urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) activate the proenzyme plasminogen by cleaving plasminogen to form the fibrinolytically active enzyme plasmin. PLGLB2 (plasminogen-like B2), also known as PLGP1, is a 96 amino acid protein that resembles the N-terminal plasminogen activation peptide, which is released from plasminogen during conversion to plasmin. PLGLB2 may bind to lysine binding sites present in the kringle structures of plasminogen, an event that interfers with the binding of fibrin or -2 antiplasmin to plasminogen and may result in the localization of activity at sites necessary for extracellular matrix destruction.