caa a22 4500 397556675 CHVBK 20180308164804.0 cr unu---uuuuu 161202e199608 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021423 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021423 Direct Interaction between Mitochondria1 Succinate-Ubiquinone and Ubiquinol-Cytochrome c Oxidoreductases Probed by Sensitivity to Quinone-Related Inhibitors [Elektronische Daten] [Atsuko Yamashita, Hideto Miyoshi, Taku Hatano, Hajime Iwamura] The electron-transfer activities of bovine heart mitochondrial complexes I, II, and III, but not complex IV, were simultaneously inhibited by 2-alkyl-4,6-dinitrophenols to a different extent. The extent of inhibition of NADH and succinate oxidase activities by dinitrophenols was compared with that of individual complex activities using submitochondrial particles. The extent of inhibition of succinate oxidase activity by 1-methylpropyl and 1-methylbutyl derivatives was much larger than that of NADH oxidase activity. This large inhibition of succinate oxidase activity seemed not to be explainable by the extent of inhibition of individual complex activities (i.e., complexes II and III activities), based upon the homogeneous ubiquinone pool model. On the other hand, other dinitrophenols (n-propyl, 1-methylpentyl, 1-methylhexyl, and tert-butyl derivatives) very similar to the above compounds did not elicit such anomalous inhibitory action, indicating that the action of 1-methylpropyl and 1-methylbutyl derivatives is highly specific to their structure. The anomalous inhibition by these two compounds was also observed with the isolated succinate-cytochrome c oxidoreductase, in which there is no ubiquinone pool behavior [Rich, P.R (1984) Biochim. Biophys. Acta 768,53-79]. However, when the succinate-cytochrome c reductase of which the activity had been partially restored by adding phospholipid and exogenous quinone to the phospholipid- and ubiquinone-depleted succinate-cytochrome c reductase was assayed, the anomalous inhibitory action of interest was undetectable. These results indicated that electron-transfer between complexes II and III, which is mediated not only by free-form, but also by protein-bound ubiquinone, occurs in the mitochondrial membrane. The fact that the anomalous inhibition of succinate oxidase activity of submitochondrial particles was sensitive to changes in the external osmotic pressure which affected the total area of the particle supports this notion. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence electron-transfer inhibitor nationallicence mitochondrial electron-transfer nationallicence succinate-ubiquinone oxidoreductase nationallicence ubiquinol-cytochrome c oxidoreductase nationallicence ubiquinone-pool nationallicence Yamashita Atsuko Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut Miyoshi Hideto Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut Hatano Taku Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut Iwamura Hajime Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut The Journal of Biochemistry Oxford University Press 120/2(1996-08), 377-384 0021-924X 120:2<377 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021423 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021423 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yamashita Atsuko Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut NATIONALLICENCE 700 1- Miyoshi Hideto Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut NATIONALLICENCE 700 1- Hatano Taku Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut NATIONALLICENCE 700 1- Iwamura Hajime Department of Agricultural Chemistry, Kyoto University, Sakyo-ku, Kyoto 606 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/2(1996-08), 377-384 0021-924X 120:2<377 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford