Hemorrhagic activity of the vascular apoptosis-inducing proteins VAP1 and VAP2 from Crotalus atrox.

Vascular apoptosis-inducing proteins (VAPs) from hemorrhagic snake venom are apoptosis-inducing toxins that target vascular endothelial cells. We now show that VAP1 and VAP2 from Crotalus atrox have hemorrhagic activity in mouse skin following intradermal injection. Following intravenous injection, VAP2 induced hemorrhage in the lung, intestine and kidney. Although the hemorrhagic activity was relatively weak, these apoptosis toxins may play a role in the complex mechanism of snake venom-induced hemorrhage.