Studies on biologically active proteinaceous substances contained in the skin mucus of the Japanese eel

1. 日本鳗鲡（Anguilla japonica）的皮肤粘液提取物经静脉注射后，对小鼠具有高度致命性。该毒素是一种分子量为40万的酸性蛋白质，由分子量为23万和11万的两种亚基组成。Gly和Ala的毒素含量丰富，而Met、Cys、Tyr和Trp的毒素含量很低。据估计，纯化毒素的LD_<50>（静脉注射小鼠）低至3.1马克/公斤。在粳稻的皮肤黏液中检测到至少两种凝集素，它们都是半乳糖相关糖的特异性凝集素。其中一个经过纯化，推测为分子量在4万-5万之间的酸性蛋白。皮肤黏液中也含有溶血素，但由于溶血素不稳定，纯化不成功。从粳稻的血清中纯化出一种蛋白毒素。纯化后的毒素内毒素LD_<50>为670马克/千克，分子量为150000。由于对粳稻皮肤毒素产生的抗血清未表现出对血清毒素的中和作用，因此两种毒素在免疫学上是可区分的。新发现的皮肤粘液中存在毒素的鱼类有：欧洲鳗鲡（Anguilla Anguilla）、梭子鳗（Muraenesox cinereus）、长鳗（conger myriaster）、泥鳅（Misgurnus anguillicaudatus）、泥鳅（sculpin Cottus pollux）和两种河豚（takifubles和Canthigaster rivulata）。鳗鲡和灰尾鳗毒素在化学和免疫学上与日本鳗鲡相似。

1. Extracts of the skin mucus of the Japanese eel Anguilla japonica were found to be highly lethal to mice when administered intravenously. The toxin was an acidic protein with a molecular weight of 400000 and was comprised of two types of subunits with molecular weights of 230000 and 110000. Gly and Ala were abundant in the toxin while Met, Cys, Tyr and Trp were very poor. The LD_<50> (i. v. injection into mice) of the purified toxin was estimated to be as low as 3.1 mug/kg.2. At least two lectins, both of which were specific to galactose-related sugars, were detected in the skin mucus of A. japonica. One of them was purified and assumed to be an acidic protein with a molecular weight of 40000-50000. Hemolysins were also contained in the skin mucus but their purification was unsuccessful due to instability.3. A proteinaceous toxin was purified from the serum of A. japonica. The purified toxin had an i. v. LD_<50> of 670 mug/kg and a molecular weight of 150000. Since no neutralization of the serum toxin was exhibited by the antiserum raised against the skin toxin of A. japonica, both toxins were immunologically distinguishable from each other.4. The presence of toxins in the skin mucus was newly established in the following fish : European eel Anguilla anguilla, pike eel Muraenesox cinereus, conger eel Conger myriaster, loach Misgurnus anguillicaudatus, sculpin Cottus pollux and two species of puffer, Takifugu niphobles and Canthigaster rivulata. The toxins of A. anguilla and M. cinereus were chemically and immunologically similar to that of A. japonica.