EFFECTS OF DIPHENYLENEIODONIUM AND OF 2,4-DICHLORODIPHENYLENEIODONIUM ON MITOCHONDRIAL REACTIONS - MECHANISM OF INHIBITION OF OXYGEN-UPTAKE AS A CONSEQUENCE OF CATALYSIS OF CHLORIDE HYDROXYL-ION EXCHANGE
EFFECTS OF DIPHENYLENEIODONIUM AND OF 2,4-DICHLORODIPHENYLENEIODONIUM ON MITOCHONDRIAL REACTIONS - MECHANISM OF INHIBITION OF OXYGEN-UPTAKE AS A CONSEQUENCE OF CATALYSIS OF CHLORIDE HYDROXYL-ION EXCHANGE
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DOI：
10.1042/bj1580317
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发表时间：
1976-01-01
影响因子：
4.1
通讯作者：
SHERRATT, HSA
中科院分区：
文献类型：
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作者：
GATLEY, SJ;SHERRATT, HSA
增加底物浓度仅少量减少二亚苯基碘鎓或 2,4-二氯亚苯基碘鎓对[大鼠肝脏]线粒体氧化的抑制作用。在Cl-存在的情况下，二亚苯基碘鎓和2,4-二氯二亚苯基碘鎓降低了线粒体基质中积累的琥珀酸盐、柠檬酸盐和谷氨酸的量，但在Cl-不存在的情况下则不然。 2,4-二氯二亚苯基碘通过线粒体氧化甘油 3-磷酸减少底物的积累。二亚苯基碘导致线粒体厌氧悬浮液碱化，Triton X-100 仅部分逆转这种情况。尽管质子脉冲的衰减速率增加，但二亚苯基碘鎓或2,4-二氯二亚苯基碘鎓不改变线粒体氧化琥珀酸的质子排出速率。 2,4-二氯二亚苯基碘鎓将完整线粒体琥珀酸氧化的最适pH值从pH 7.2改变至8.0，而对冻融线粒体（pH 8.0）没有影响。吸氧的绝对率越高，抑制呼吸作用50%所需的2,4-二氯苯碘鎓浓度越低。 EDTA，而非 EGTA [乙二氧基双（乙胺）-四乙酸] 增加了二亚苯基碘鎓、2,4-二氯二亚苯基碘鎓和三正丙基锡对呼吸的抑制作用。二亚苯基碘鎓和 2,4-二氯二亚苯基碘鎓通过引起基质酸化来限制含 Cl 介质中的呼吸，并且在 NADH 和琥珀酸之间以及琥珀酸和细胞色素 c 之间的呼吸链中存在 pH 敏感位点。
Increasing the substrate concentration only decreased the inhibition of [rat liver] mitochondrial oxidations by diphenyleneiodonium or by 2,4-dichlorophenyleneiodonium by a small amount. Diphenyleneiodonium and 2,4-dichlorodiphenyleneiodonium lowered the amounts of succinate, citrate and glutamate accumulated in the matrix of mitochondria in the matrix of mitochondria in the presence of Cl-, but not in its absence. 2,4-Dichlorodiphenyleneiodonium decreased the accumulation of substrates by mitochondira oxidizing glycerol 3-phosphate. Diphenyleneiodonium caused an alkalinization of the medium with an anaerobic suspension of mitochondria, which was only partly reversed by Triton X-100. The rate of proton extrusion by mitochondria oxidizing succinate was not altered by diphenyleneiodonium or by 2,4-dichlorodiphenyleneiodonium, although the rate of decay of proton pulses was increased. 2,4-Dichlorodiphenyleneiodonium shifted the pH optimum for succinate oxidation by intact mitochondria from pH 7.2 to 8.0, whereas there was no effect on that the freeze-thawed mitochondria, which was pH 8.0. The concentration of 2,4-dichlorophenyleneiodonium required to inhibit respiration by 50% is less the higher the absolute rate of oxygen uptake. EDTA, but not EGTA [ethanedioxybis(ethylamine)-tetra-acetic acid] increased the inhibition of respiration by diphenyleneiodonium, 2,4-dichlorodiphenyleneiodonium and by tri-n-propyltin. Diphenyleneiodonium and 2,4-dichlorodiphenyleneiodonium limit respiration in Cl-containing medium by causing an acidification of the matrix, and there are pH-sensitive sites in the respiratory chain between NADH and succinate, and between succinate and cytochrome c.