Biochemical studies on proteinaceous toxins in the skin mucus and roe of the lamprey Lampetra japonica

1. 在日本七鳃鳗（Lampetra japonica）的皮肤粘液和鱼卵中发现了多蛋白毒素。估计1克皮肤粘液和卵分别杀死70只和215-800只体重为20克的小鼠。两种毒素均无凝血和溶血活性；鱼子毒素也缺乏抗菌活性。黏液毒素非常不稳定，因此无法提纯。另一方面，通过cm -纤维素和羟基磷灰石的柱层析和Mono上的FPLC纯化得到了电泳纯的鱼子毒素，纯化后的毒素经小鼠静脉注射具有较高的致死活性；LD_<50>估计为33马克/公斤。它是碱性的，在不含2-聚巯基醇的情况下，通过SDS-PAGE测定其分子量为40,000，在有还原试剂存在的情况下，通过SDS-PAGE分析发现该毒素由分子量为30,000和10,000的两种亚基组成。氨基酸组成的特点是含硫氨基酸（半胱氨酸和蛋氨酸）含量低。在21种被检测的鱼类中，没有一种鱼类的卵中含有毒素。相比之下，54种鱼类中有9种被发现在皮肤粘液中含有毒素。鳗鲡（Anguilla japonica）、鳗鲡（Anguilla Anguilla）和鳗鲡（Muraenesox cinereus） 3种剧毒的毒素均为酸性蛋白质，分子量约为40万。它们在免疫学上也彼此相似。鞘氨醇和神经节苷对日本刺鱼和鳗鲡毒素的致死活性均有抑制作用。

1. Plroteinaceous toxins were newly found in the skin mucus and roe of the lamprey Lampetra japonica. One gram of the skin mucus and roe was evaluated to kill 70 and 215-800 mice with a body weight of 20g, respectively. Both toxins showed no hemagglutinating and hemolytic activities ; the roe toxin also lacked antimicrobial activity.2. The mucus toxin was very unstable and hence its purification was not achieved. On the other hand, the roe toxin was purified to an electrophoretically pure state by column chromatography on CM-cellulose and hydroxyapatite and FPLC on Mono S.The purified toxin exhibited high lethal activity upon i.v. injection into mice ; the LD_<50> was estimated to be 33 mug/kg. It was basic in nature and its molecular weight was determined to be 40,000 by SDS-PAGE in the absence of 2-mer captocthanal, Analysis by SDS-PAGE in the presence of the reducing reagent revealed that the toxin was comprised of two kinds of subunits with molecular weights of 30,000 and 10,000. The amino acid composition was characterized by low contents of sulfur-containing amino acids (half-Cys and Met).3. None of the 21 species of fish examined had toxins in their roes. in contrast, as many as 9 of 54 species of fish were found to contain toxins in the skin mucus. Toxins in 3 species of anguillid fish (Anguilla japonica, Anguilla anguilla and Muraenesox cinereus), which were highly toxic, were all acidic proteins with a molecular weight of about 400,000. They were also immunologically comparable to one another. It was noticeable that sphingosine and gangliosides showed inhibitory effects on the lethal activity of the A.japonica and A.anguilla toxins.