Ruben G C, Telford J N, Carroll R C
J Cell Biol. 1976 Mar;68(3):724-39. doi: 10.1083/jcb.68.3.724.
Cytochrome oxidase vesicles with high oxidase activity and respiratory control ratio (greater than 3.5) were characterized by the freeze-etch technique for electron microscopy. By the use of this technique, cytochrome oxidase is shown to be an inner membrane particle. By locating cross-fractured vesicles in the same preparation, cytochrome oxidase particles are shown to extend across the phospholipid bilayer membranes. When cytochrome oxidase is added to preformed liposomes respiratory control is not observed, but high oxidase activity is maintained. In this preparation the cytochrome oxidase particles are located on the outer vesicle membrane surface. These observations provide direct evidence that cytochrome oxidase is found in a transmembranous position in closed, activecytochrome oxidase vesicles having respiratory control.
具有高氧化酶活性和呼吸控制率(大于3.5)的细胞色素氧化酶囊泡,通过用于电子显微镜检查的冷冻蚀刻技术进行了表征。通过使用该技术,细胞色素氧化酶显示为内膜颗粒。通过在同一制剂中定位交叉断裂的囊泡,细胞色素氧化酶颗粒显示延伸穿过磷脂双分子层膜。当将细胞色素氧化酶添加到预先形成的脂质体中时,未观察到呼吸控制,但保持了高氧化酶活性。在该制剂中,细胞色素氧化酶颗粒位于囊泡外膜表面。这些观察结果提供了直接证据,表明在具有呼吸控制的封闭、活性细胞色素氧化酶囊泡中,细胞色素氧化酶处于跨膜位置。