Agkistrodon acutus venom thrombin-like enzymes and antithrombin factors (AaV-TLE/AF)

Agkistrodon acutus venom thrombin-like enzymes (TLEs) and antithrombin factors represent a complex group of proteins found in the venom of the sharp-nosed pit viper, a medically significant snake in East Asia [4]. TLEs, such as acutin and acutobin, are serine proteases that functionally mimic human thrombin by cleaving fibrinogen into fibrin; however, they typically do not activate Factor XIII, resulting in the formation of unstable, easily degraded fibrin polymers and subsequent systemic defibrinogenation [1][2]. Antithrombin factors, often belonging to the C-type lectin-like protein family, further disrupt hemostasis by directly binding to and inhibiting thrombin or other critical coagulation factors like Factor X [3]. Clinically, these proteins are the primary targets for neutralization by specific antivenoms during the management of snakebite envenomation, which is characterized by severe coagulopathy and hemorrhage [4]. Beyond their toxicological role, purified TLEs from this species have been investigated as therapeutic defibrinogenating agents for treating thrombotic disorders, such as ischemic stroke, by reducing blood viscosity and preventing further clot growth [2]. Monitoring the activity of these components in patients involves measuring coagulation parameters like plasma fibrinogen levels and prothrombin time.

Other names

AcutinAcutobinAaACSharp-nosed pit viper venom thrombin-like enzymeAgkistrodon acutus anticoagulant factorHundred-pacer venom proteases

Thrombin-like enzymes (TLEs) catalyze the release of fibrinopeptides from fibrinogen to form unstable fibrin clots, leading to consumptive defibrinogenation [1][2]. Antithrombin factors bind to and inhibit the activity of thrombin or other coagulation factors, preventing the conversion of fibrinogen to fibrin [3].