Plasminogen lysine-binding sites (LBS)

The lysine-binding sites (LBS) are specialized protein domains located within the Kringle structures of plasminogen and its active form, plasmin. These sites play a critical role in the regulation of fibrinolysis by mediating the binding of plasminogen to the C-terminal lysine residues of partially degraded fibrin [1, 4]. By localizing plasminogen to the fibrin clot, these sites facilitate its activation by tissue plasminogen activator (tPA) and ensure efficient clot dissolution. In clinical practice, these sites are the primary targets for antifibrinolytic drugs such as tranexamic acid and aminocaproic acid, which act as lysine analogs [2, 3]. These drugs competitively occupy the LBS, preventing the enzyme from associating with fibrin and thereby inhibiting the breakdown of blood clots. This mechanism is vital for managing conditions characterized by excessive bleeding, such as heavy menstrual bleeding, surgical hemorrhage, and trauma-induced coagulopathy [2].

Other names

Plasmin lysine-binding sitesKringle domainsLBSPlasminogen LBS

Competitive inhibition of plasminogen and plasmin binding to fibrin lysine residues, thereby preventing fibrinolysis.