Release of tetrodotoxin and paralytic shellfish poison from puffer liver by RNase

A nontoxic high-molecular fraction was separated from the extracts of toxic liver of a puffer, Takifugu poecilonotus, by Sephadex G-50 gel filtration. This fraction became toxic when digested with RNase T2. The toxins were partially purified by activated charcoal treatment, followed by chromatography on Bio-Gel P-2 and Bio-Rex 70, and were analyzed by TLC and electrophoresis. The results showed that most of the toxicity is accounted for by tetrodotoxin, and the remainder by saxitoxin and other unidentified toxins. The corresponding high-molecular fraction separated from nontoxic liver of another puffer, T. rubripes, did not release any toxin on RNase digestion.