Fibrinogen gamma-prime chain (γ′ fibrinogen) (γ′ fibrinogen)

The fibrinogen gamma-prime (γ′) chain is an alternative splice variant of the fibrinogen gamma gene (FGG), constituting roughly 8-15% of the total fibrinogen pool in human plasma [UniProt P02679]. It differs from the more common γA chain by the replacement of the last four amino acids with a unique 20-amino acid sequence that is highly anionic and contains sulfated tyrosine residues [PubMed: 12855588]. This specific C-terminal extension enables high-affinity binding to thrombin at exosite II and to Factor XIII, effectively sequestering thrombin within the developing fibrin clot—a phenomenon referred to as antithrombin I activity [PubMed: 15507140]. By binding thrombin, γ′ fibrinogen protects it from inactivation by the heparin-antithrombin complex while simultaneously limiting its availability to other substrates, thereby modulating the overall thrombotic potential [PubMed: 19154363]. Clinically, elevated levels of γ′ fibrinogen are recognized as a significant biomarker for arterial thrombotic diseases, such as myocardial infarction and ischemic stroke, because they contribute to the formation of fibrin networks that are denser and more resistant to fibrinolysis [PubMed: 23539245]. Although no drugs currently target the γ′ chain specifically, it remains a subject of intense research for the development of novel anticoagulants that could disrupt its interaction with thrombin to improve clot permeability and susceptibility to lysis.

Other names

Fibrinogen gamma-BFGG-gamma primeGamma-prime fibrinogenFibrinogen gamma-prime variant

Sequestration of thrombin via exosite II binding, which limits thrombin's availability for other procoagulant activities while protecting it from heparin-antithrombin inhibition [PubMed: 19154363].