Institute of Botany, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
Plant Physiol. 1985 Mar;77(3):758-64. doi: 10.1104/pp.77.3.758.
The functional and thermodynamic characteristics of the ubiquinolcytochrome (Cyt) c oxidoreductase in a Cyt b/c(1)-enriched fraction (defined S-1) isolated from Jerusalem artichoke mitochondria (JAM) (Helianthus tuberosus), have been analyzed. Fraction S-1, obtained through deoxycholate-KCl fractionation procedure, contained one Cyt of c type (formally c(1) with Em(7.0) of +240 millivolts), two b type Cyt with Em(7.0) values of +100 and -25 millivolts, ferredoxin-like centers presumably linked to succinic- and NADH-dehydrogenases, and a Rieske-type iron sulfur center (g(y) = 1.89). The ubiquinol-dependent Cyt c reduction by fraction S-1 showed sensitivity to antimycin A, myxothiazol, and n-2-hepthyl-1-hydroxyquinoline N-oxide with I(50) of 12 nanomolar, 30 nanomolar, and 0.1 micromolar, respectively. Oxidation-induced extra b type reduction, a widespread phenomenon of bacterial and mitochondrial respiratory systems, has also been observed in both intact mitochondria and S-1 fraction. The data seem to blur previous experiments in which both spectral and functional differences between higher plant and mammalian mitochondria have been underlined.
已分析了从朝鲜蓟线粒体（Helianthus tuberosus）中分离出的富含 Cyt b/c(1) 的 Cyt b/c(1)-细胞色素 c 氧化还原酶（Cyt c oxidoreductase）在功能和热力学特性方面的特征（定义为 S-1 部分）。通过脱氧胆酸盐-KCl 分级分离程序获得的 S-1 部分包含一个 Cyt c 型（正式的 c(1)，Em(7.0)为+240 毫伏），两个 Cyt b 型，Em(7.0)值分别为+100 和-25 毫伏，铁氧还蛋白样中心可能与琥珀酸脱氢酶和 NADH 脱氢酶相连，以及一个 Rieske 型铁硫中心（g(y) = 1.89）。S-1 部分的细胞色素 c 还原依赖于细胞色素 c，对 Antimycin A、Myxothiazol 和 N-2-hepthyl-1-hydroxyquinoline N-oxide 敏感，I(50)分别为 12 纳摩尔、30 纳摩尔和 0.1 微摩尔。氧化诱导的额外 b 型还原是细菌和线粒体呼吸系统的一种广泛现象，在完整的线粒体和 S-1 部分中也观察到了这种现象。这些数据似乎模糊了以前的实验，以前的实验强调了高等植物和哺乳动物线粒体之间在光谱和功能方面的差异。
