Umbach A L, Wiskich J T, Siedow J N
Department of Botany, Duke University, Durham, NC 27708-0338.
FEBS Lett. 1994 Jul 11;348(2):181-4. doi: 10.1016/0014-5793(94)00600-8.
Two factors known to regulate plant mitochondrial cyanide-resistant alternative oxidase activity, pyruvate and the redox status of the enzyme's intermolecular disulfide bond, were shown to differently affect activity in isolated soybean seedling mitochondria. Pyruvate stimulated alternative oxidase activity at low levels of reduced ubiquinone, shifting the threshold level of ubiquinone reduction for enzyme activity to a lower value. The disulfide bond redox status determined the maximum enzyme activity obtainable in the presence of pyruvate, with the highest rates occurring when the bond was reduced. With variations in cellular pyruvate levels and in the proportion of reduced alternative oxidase protein, a wide range of enzyme activity is possible in vivo.
已知调节植物线粒体抗氰交替氧化酶活性的两个因素，即丙酮酸和该酶分子间二硫键的氧化还原状态，对离体大豆幼苗线粒体中的活性有不同影响。在泛醌还原水平较低时，丙酮酸刺激交替氧化酶活性，将酶活性所需的泛醌还原阈值水平降低。二硫键的氧化还原状态决定了丙酮酸存在时可获得的最大酶活性，当二硫键还原时酶活性速率最高。随着细胞内丙酮酸水平以及还原态交替氧化酶蛋白比例的变化，体内可能存在广泛的酶活性范围。
