Snake venom hemorrhagins

Viperine and crotaline snake venoms contain one or more hemorrhagic princip les called hemorrhagins. These are zinc-containing metalloproteases charact erized by the presence of a protease domain, with additional domains in som e of them. They act essentially by degrading the component proteins of base ment membrane underlying capillary endothelial cells. The toxins also act o n these cells causing lysis or drifting apart, resulting in hemorrhage per rhexis or per diapedesis. Some of these toxins have been found to exert add itional effects such as fibrinogenolysis and platelet aggregation that faci litate hemorrhage. The structural and functional features of this class of toxins have been discussed in this review in an attempt to get a better und erstanding of their toxicity. This can be of immense therapeutic value in t he management of snake venom poisoning, as hemorrhagins are among the major lethal factors in snake venom.