Møller I M, Kay C J, Palmer J M
Biochem J. 1986 Aug 1;237(3):765-71. doi: 10.1042/bj2370765.
The oxidation of NADH or succinate by Jerusalem-artichoke (Helianthus tuberosus L.) mitochondria in the presence of chlortetracycline induced an increase in chlortetracycline fluorescence. Any treatment that prevented the formation of a transmembrane potential (as monitored by changes in safranine absorbance, A511-A533), e.g. uncoupling with carbonyl cyanide p-trifluoromethoxyphenylhydrazone, inhibition of dehydrogenase activity or electron transport, anaerobiosis or depletion of substrate, prevented the increase in chlortetracycline fluorescence or caused it to disappear. Changes in chlortetracycline fluorescence were always slower than changes in the safranine absorbance. The increase in chlortetracycline fluorescence caused by succinate oxidation had an excitation maximum at 393 nm, indicating that a Ca2+-chlortetracycline complex was involved. The increase in fluorescence was observed even in the presence of EDTA, which removes all external bivalent cations, indicating that internal Ca2+ is mobilized. Although NADH and succinate oxidations gave the same membrane potential and qualitatively had the same effect on chlortetracycline fluorescence, NADH oxidation caused a much larger (over 3-fold) increase in chlortetracycline fluorescence than did succinate oxidation. It is possible that this is connected with the Ca2+-dependence of NADH oxidation. In the presence of 2 mM external Ca2+, chlortetracycline collapsed the transmembrane potential and uncoupled succinate and duroquinone oxidation.
在金霉素存在的情况下，菊芋（Helianthus tuberosus L.）线粒体对NADH或琥珀酸的氧化会导致金霉素荧光增强。任何阻止跨膜电位形成的处理（通过番红吸收度变化A511 - A533监测），例如用羰基氰对三氟甲氧基苯腙解偶联、抑制脱氢酶活性或电子传递、厌氧或底物耗尽，都会阻止金霉素荧光增强或使其消失。金霉素荧光的变化总是比番红吸收度的变化慢。琥珀酸氧化引起的金霉素荧光增强在393 nm处有最大激发波长，表明涉及Ca2 + - 金霉素复合物。即使在存在能去除所有外部二价阳离子的EDTA的情况下也观察到荧光增强，这表明内部Ca2 +被动员。尽管NADH和琥珀酸氧化产生相同的膜电位，并且在定性上对金霉素荧光有相同的影响，但NADH氧化引起的金霉素荧光增强比琥珀酸氧化大得多（超过3倍）。这可能与NADH氧化对Ca2 +的依赖性有关。在存在2 mM外部Ca2 +的情况下，金霉素会破坏跨膜电位并使琥珀酸和杜罗醌氧化解偶联。
