Snake venom protein toxins from viperid species (SVPs)

Snake venom protein toxins from viperid species are a complex array of enzymes and non-enzymatic proteins that drive the clinical manifestations of envenomation by vipers and pit vipers (Gutierrez et al., 2017). These toxins primarily include snake venom metalloproteinases (SVMPs), which degrade the extracellular matrix and cause hemorrhage, and phospholipases A2 (PLA2s), which contribute to inflammation, myotoxicity, and neurotoxicity (Slagboom et al., 2017). Biologically, they function by disrupting the hemostatic system, damaging vascular integrity, and inducing local tissue necrosis. In clinical practice, these proteins are the primary targets for antivenom therapies, which utilize purified antibodies to neutralize circulating toxins and prevent systemic complications (Warrell, 2010). Beyond their role in pathology, these toxins have been pivotal in drug discovery, serving as the structural basis for medications such as ACE inhibitors and antiplatelet drugs like eptifibatide (King, 2011). Current research is focused on developing small-molecule inhibitors to complement antivenoms, aiming to provide more accessible and rapid treatment for snakebite victims (Lewin et al., 2016).

Other names

Viperid toxinsViper venom proteinsCrotalinae toxinsViperinae toxinsSnake venom proteins

The primary mechanism of action for drugs targeting these toxins involves immunological neutralization; antivenoms (e.g., CroFab) contain F(ab) or F(ab')2 fragments that bind to the toxins' antigenic sites, preventing them from reaching or binding to their physiological targets (Gutierrez et al., 2017). Emerging small-molecule therapeutics, such as varespladib, act as competitive inhibitors that bind to the active site of enzymatic toxins like phospholipase A2 (PLA2), thereby blocking their catalytic activity and preventing downstream tissue damage and systemic toxicity (Lewin et al., 2016). Other inhibitors, such as marimastat or unithiol, target the zinc-dependent catalytic site of snake venom metalloproteinases (SVMPs) to inhibit proteolysis and hemorrhage (Albulescu et al., 2020).