摘要
经Sephadex G-50,sp-Sephadex C-25二步柱层析法,从山东马氏钳蝎(Bu-thus martensii Karch)粗毒中分离出四种对美洲(虫非)蠊有强直麻痹反应的毒性蛋白组份。其中二个组分在SDS聚丙烯酰胺电泳和等电聚焦电泳上均呈现单一区带,命名为BmK IT-Ⅰ,BmK IT-Ⅱ其pI分别为8.2和8.4,分子量分别为8400和7560。同时还分析了二个组份的氨基酸组成。经DABITC/PITC双偶合法测定了BmKIT-Ⅰ和BmK IT-Ⅱ的N端部份氨基酸排列顺序,它们分别为H_2NVal.Arg.Asp.Ala……H_2NVal.Arg.Asp.Gly……。 电生理学研究表明,纯化的BmK IT-I(1×10^(-5)g/ml)对(虫非)蠊腹Ⅵ神经节的突触传递有阻断作用,阻断后用生理溶液洗,则突触传递可恢复。从同一蝎毒粗毒中分离纯化的哺乳动物类神经毒素BmKⅢ在浓度高出100倍(1×10^(-3)g/ml)时也可以阻断(虫非)蠊腹Ⅵ神经节的突触传递,但用生理溶液冲洗没有观察到恢复。
Four insect toxic components were obtained from the crude venom of scorpion Buthus martensii Karch by Sephadex G-50 gel filtration and rechromatogra-phy on sp-Sephadex C-25. They induced excitatory paralysis symptoms to cockroach Periplaneta americana.The results of isoelectric focusing electrophoresis and SDS PAGE of two insect toxic fractions showed they are homogeneous. Named BmK IT-Ⅰ and BmK IT-Ⅱ .BmK IT-Ⅰ is composed of 70 amino acids including eight cystines, and with a pI value of 8.2, BmK IT-Ⅱ is composed of 63 amino acids including six cysteines, and with a pI value of 8.4. They have molecular weight of 8400 and 7900 as determined by SDS PAGE, and 8400 and 7560 as calculated from the amino acid composition respectively. N-terminal partial sequenes of BmK IT-Ⅰ and BmK IT-Ⅱ determined byDABITC/PITC method are Val-Arg-Asp-Ala……and Val-Arg-Asp-Gly……respectively.The effect of BmK IT-Ⅰ on the synaptic transmission in the 6th abdominal ganglion of the cockroach (Periplaneta americana) was investigated with mannitol gap method. The results showed that BmK IT-Ⅰ (1×10-5g/ml) could reversibly block the transmission between cereal nerves-giant axons. However the pure mammalian toxin (BmK Ⅲ), isolated from the same crude venom, could irreversibly block the synaptic transmission of the same preparation only at a much higher concentra tion (1×10-3g/ml)
关键词
蝎毒
昆虫类神经毒素
纯化
Scorpion venom Insect toxic component Purification
