Two toxins from the venom of Trimeresurus tokarensis

1. Two toxins, Tokaratoxin-1 (TT-1) and Tokaratoxin-2 (TT-2), were isolated from the venom of Trimeresurus tokarensis using gel filtration on a Sephadex G-100 column, followed by chromatography on DEAE-Sephacel and carboxymethyl-cellulose. TT-1 possessed both hemorrhagic and proteolytic activities. However, TT-2 did not show hemorrhagic activity. 2. Homogeneity was established by the formation of a single band in acrylamide gel electrophoresis, isoelectric focusing and SDS-PAGE. 3. Molecular weights of TT-1 and TT-2 were 71,000 and 25,400, respectively. Although TT-2 is a basic protein, TT-1 is an acidic protein. 4. Biological activities of TT-1 and TT-2 were inhibited by EDTA, EGTA and o-phenanthroline, suggesting that the toxins are metalloproteins. Atomic absorption analyses indicated that TT-1 contains 2.79 mol Ca/mol protein and TT-2 contains 1.04 mol Ca/mol protein and 1.07 mol Zn/mol protein, respectively. 5. The two toxins degraded the A alpha and B beta chains of fibrinogen. 6. TT-1 induced necrosis in addition to its hemorrhagic activity while TT-2 induced necrosis only.