Snake venom components affecting blood coagulation and the vascular system: structural similarities and marked diversity.

In studies of blood coagulation and the vascular system, snake venom toxins have been indispensable in elucidating the complex physiological mechanisms that govern coagulation and the vascular system in mammals, given their potency and highly specific biological effects. The various components of snake venom toxins can be classified according to their mechanism of action, for example, serine proteases, metalloproteinases, Kunitz-type protease inhibitors, phospholipases A(2), (L)-amino acid oxidases, C-type lectin(-like) proteins, disintegrins, vascular endothelial growth factors, three-finger toxins, and cysteine-rich secretory proteins. Although the molecular structures of most toxins are not unique to snake venom toxins, venom proteins often exhibit marked diversity in their biological effects, despite their structural similarities. In this review, we identify several snake venom toxins capable of affecting blood coagulation and the vascular system, as well as various toxins from other organisms, including leeches and ticks.