Mendel-Hartvig I, Nelson B D
Biochim Biophys Acta. 1981 Jun 12;636(1):91-7. doi: 10.1016/0005-2728(81)90079-7.
Core proteins I (Mr 50 000) and II (Mr 47 000) were isolated from beef heart ubiquinol-cytochrome c reductase, and radioimmunoassays were developed for both. Immunoreplica experiments show that antisera against each protein react with a single peptide in both isolated Complex III and in mitochondria. Thus, core proteins are not aggregated forms of smaller peptides as suggested for the yeast protein (Jeffrey, A., Power, S. and Palmer, G., Biochem. Biophys. Res. Commun. (1979) 86, 271-277). Core proteins were quantitated in Complex III and in mitochondria using radioimmunoassay. Approx. 2 mol core protein II per mol core protein I were found. A molar ratio of 1 : 2 : 2 : 1 is suggested for core protein I : core protein II : cytochrome b : cytochrome c1. Radioimmunoassay shows that the antibodies react as extensively with Complex III-bound core protein as with the isolated core proteins. In spite of this, the antibodies do not inhibit electron transport in submitochondrial particles or isolated Complex III, and they have no oligomycin- or uncoupler-like effects on submitochondrial particles oxidizing NADH. The combined results from radioimmunoassay and immunoreplica experiments strongly suggest, however, that core proteins are specifically associated with Complex III in the mitochondria, implying a specific role there.
核心蛋白I（分子量50 000）和核心蛋白II（分子量47 000）是从牛心泛醇 - 细胞色素c还原酶中分离出来的，并且针对这两种蛋白都开发了放射免疫测定法。免疫复型实验表明，针对每种蛋白的抗血清在分离的复合物III和线粒体中均与单一肽段发生反应。因此，核心蛋白并非如酵母蛋白那样是较小肽段的聚集形式（杰弗里，A.，鲍尔，S.和帕尔默，G.，《生物化学与生物物理研究通讯》（1979年）86卷，271 - 277页）。使用放射免疫测定法定量了复合物III和线粒体中的核心蛋白。发现每摩尔核心蛋白I大约有2摩尔核心蛋白II。推测核心蛋白I：核心蛋白II：细胞色素b：细胞色素c1的摩尔比为1：2：2：1。放射免疫测定表明，抗体与结合在复合物III上的核心蛋白的反应程度与与分离的核心蛋白的反应程度相同。尽管如此，这些抗体并不抑制亚线粒体颗粒或分离的复合物III中的电子传递，并且它们对氧化NADH的亚线粒体颗粒没有寡霉素或解偶联剂样的作用。然而，放射免疫测定和免疫复型实验的综合结果强烈表明，核心蛋白在线粒体中与复合物III特异性相关，这意味着它们在那里具有特定作用。
