Tetrodotoxin binding protein

Matsui, T., Yamamori, K., Furukawa, K., Kono, M., 2000. Purification and some properties of a tetrodotoxin binding protein from the blood plasma of Kusafiigu, Takiftigu niphoblos. Toxicon, 38 463 168. 

Ion channels have been purified from several types of excitable cells. The proteins that make up the voltage-gated Na+ channels of brain neurons were first identified by labeling them with reactive derivatives of neurotoxins obtained from scorpions. Intact channels were purified from both brain and muscle after solubilization with detergents. When the purified proteins were incorporated into phospholipid vesicles or planar bilayer membranes, they were found to conduct Na+ across the membrane. The ion specificity of the reconstituted channels and the alterations of the conductance in response to changes in Aift or to various neurotoxins were similar to the properties of the original nerve or muscle membranes. In addition to scorpion toxins, a variety of other specific neurotoxins bind to the purified channels and inhibit their activities. These include tetrodotoxin (a poison obtained from... 

Like the acetylcholine receptor channel, the sodium channel also was purified on the basis of its ability to bind a specific neurotoxin. Tetrodotoxin, an organic compound isolated from the puffer fish, binds to sodium channels with great avidity (K nM). The lethal dose of this poison for an adult human being is about 10 ng. The sodium channel was first purified from the electric organ of electric eel, which is a rich source of the protein forming this channel. The isolated protein is a single chain of 260 kd. 

---