PROTEINS ISOLATED FROM THE VENOM OF THE COMMON TIGER SNAKE (NOTECHIS-SCUTATUS-SCUTATUS) PROMOTE HYPOTENSION AND HEMORRHAGE

Notechis scutatus scutatus venom contains several toxic acidic protein s called HT(a-i) which promote hypotension and hemorrhage in mice. The y have apparent mol. wts in the 18,000-21,000 range, i.v. LD50 values between 0.5 and 1.5 mug/g, and no detectable phospholipase, arginine e sterase, proteolytic or hemolytic activities. A polyclonal antibody ra ised against HT(g) binds to other purified proteins, suggesting that t hey are isoforms of the same protein. Many other elapid crude venoms c ontain proteins which recognize the polyclonal antibody raised against HT(g). Crotalid and viperid crude venoms do not recognize this antibo dy, although some of their component proteins are known to exhibit hyp otensive and hemorrhagic activities. A combination of gel-filtration o n Sephacryl S-200, cation-exchange and anion-exchange chromatography a llows isolation of the N. s. scutatus proteins in high purity. They ar e the first hypotension-inducing proteins to be purified from an Austr alian elapid.