SeO_3^（2－）及SeO_3^（2－）和半胱氨酸或还原型谷胱甘肽联用对牛脑V

Effect of SeO_3￣(2-) and SeO_3￣(2-) Combined with Cysteine or Glutathione(reduced form)on Activity of the H￣+-Translocating ATPase Complex of ClathrinCoated Vesicles from Bovine Brain

Ｓｅ_３^（２－）对牛脑Ｖ型质子转运ＡＴＰ酶复合体活力呈现明显的抑制作用。这种抑制作用具有对剂量和预保温时间的依赖关系，且不被稀释效应所恢复，但过量的ＤＴＴ可去除这种抑制作用。半胱氨酸对这种抑制作用呈双功能效应。低浓度时促进抑制作用，高浓度时部分恢复抑制作用。还原型谷胱甘肽与半胱氨酸有类似效应。但促进抑制作用没有半胱氨酸强，而恢复抑制作用却较半胱氨酸强。ＳＤＳ聚丙烯酰胺凝胶电泳和放射自显影图谱表明，ＳｅＯ_３^（２－）和半脱氨酸优先结合在７０ｋＤ亚基上。并且验证了ＡＴＰ酶复合体的－ＳＨ基和ＳｅＯ_３^（２－）及半胱氨酸的－ＳＨ基以－Ｓ－Ｓｅ－Ｓ－键相连接。根据上述结果，讨论了７０ｋＤ亚基的－ＳＨ基及其相关的结构域涉及到ＡＴＰ酶的活性中心，７０ｋＤ亚基可能是ＡＴＰ酶复合体的水解活性亚基。

The activity of the H+-translocating ATPase complex of clathrin-coated vesicles was significantly inhibited by SeO_3￣(2-). The concentration and time of preincubation dependency of the inhibition by SeO_3￣(2-)were observed. The inhibition could not be reversed by dilution but could be abolished by DTT. Cysteine showed a bi-functional effect on the inhibition of the H￣+-ATPase complex by SeO_3￣(2-) , i. e. , it facilitated the inhibtion at low concentration, but partially reversed the inhibition at high concentration. Glutathione (reduced form) showed similar effect on the inhibition as those of cysteine dose, but facilitating effect was weaker than that of cysteine and reverse effect was stronger. SDS-PAGE and autoradiographic patterns indicated that SeO and cysteine were first combined with the 70kD subunit of the ATPase complex and that-SH of the ATPase ,SeO_3￣(2-)and -SH of cysteine were linked in the form of -S-Se-S-. The SHgroup of the 70kD subunit and its related domain being located nearby the active center of the ATPase complex were discussed. It was suggested that the 70kD subunit may be the hydrolytic subunit of the ATPase complex.