Purification and characterization of patagonfibrase, a metalloproteinase showing α-fibrinogenolytic and hemorrhagic activities, from Philodryas patagoniensis snake venom

Venoms of Colubridae snakes are a rich source of novel compounds, which may have applications in medicine and biochemistry. In the present study, we describe the purification and characterization of a metalloproteinase (patagonfibrase), the first protein to be isolated from Philodryas patagoniensis (Colubridae) snake venom. Patagonfibrase is a single-chain protein, showing a molecular mass of 53,224 Da and an acidic isoelectric point (5.8). It hydrolyzed selectively the Aα-chain of fibrinogen and when incubated with fibrinogen or plasma, the thrombin clotting time was prolonged. Prominent hemorrhage developed in mouse skin after intradermal injection of patagonfibrase. When administered into mouse gastrocnemius muscle, it induced local hemorrhage and necrosis, and systemic bleeding in lungs. Patagonfibrase showed proteolytic activity toward azocasein, which was enhanced by Ca2+ and inhibited by Zn2+, cysteine, dithiothreitol and Na2EDTA. Patagonfibrase impaired platelet aggregation induced by collagen and ADP. Thus, patagonfibrase may play a key role in the pathogenesis of disturbances that occur in P. patagoniensis envenomation, and may be used as a biological tool to explore many facets of hemostasis.