Mole vipers

Endothehns constitute a family of peptides (Hart and Hart, 1992). They are very potent endogenous vasoconstrictors and vasopressors and are secreted by various cells and tissues in the human body. Of the three isoforms, endothe-hn-1 (ET-1) is one of the most potent contractors of vascular smooth muscles (Miller et al, 1993). Endothelins have very similar structures and biological properties to sarafotoxins (Kloog and Sokolovsky, 1989), and the toxic peptides are obtained from the venom of mole vipers (Atractaspidae). 

Snake venoms, particularly those from North American pit vipers, contain direct-acting fibrinolytic proteinases (13). Fibrolase is the fibrinolytic enzyme from southern copperhead venom (14). Fibrolase is a non-glycosylated metalloproteinase with a molecular weight of 23,000 it contains one mole of zinc per mole of protein (14). The enzyme has an isoelectric point of approximately pH 6.8. The amino acid sequence of the enzyme has been determined... 

---