Specific Interaction of Cytokinins and Their Analogs with Rotenone-sensitive Internal NADH Dehydrogenase in Potato Tuber Mitochondria
作者:Masayuki Sue、Hideto Miyoshi、Hajime Iwamura
DOI:10.1271/bbb.61.1806
日期:1997.1
Effects of cytokinins were studied on rotenone-sensitive NADH dehydrogenase in mitochondria from fresh potato tubers (Solarium tuberosum), in consideration of the operation of external and rotenone-insensitive internal NADH dehydrogenases that has not been fully accounted for in previous studies. In submitochondrial particles (smp), zeatin was only weakly active, and zeatin riboside (ZR) was inactive. Inhibition rates at 400 μM of isopentenyladenine (iP) and isopentenyladenosine (iPA) were 45% and 30%, respectively, and that of BA (BA) was 64%. In intact mitochondria, the inhibition by iP and BA significantly increased, I50 being 50 and 250 μM, respectively, but that by zeatin and iPA decreased. A structure–activity study showed that hydrophobic and steric factors are important for the activity. Cytokinins inhibited the electron flow via natural quinone more strongly than that via synthetic quinone. These results suggest that among the cytokinins the species that can regulate the electron transport is iP rather than its riboside or zeatin.
在新鲜土豆块茎(Solarium tuberosum)的线粒体中,研究了细胞分裂素对鱼藤酮敏感的NADH脱氢酶的影响,考虑到先前研究中未充分解释的外部和鱼藤酮不敏感的内部NADH脱氢酶的作用。在亚线粒体颗粒(smp)中,玉米素仅微弱活跃,而玉米素核苷(ZR)则不活跃。异戊烯腺嘌呤(iP)和异戊烯腺苷(iPA)在400 μM时的抑制率分别为45%和30%,而BA(BA)的抑制率为64%。在完整的线粒体中,iP和BA的抑制显著增加,I50分别为50和250 μM,而玉米素和iPA的抑制则降低。结构-活性研究表明,疏水性和立体因素对活性很重要。细胞分裂素通过天然醌抑制电子流动的强度大于通过合成醌的抑制。这些结果表明,在细胞分裂素中,调节电子传输的种类是iP而不是其核苷或玉米素。