Dunn P P, Slabas A R, Cottingham I R, Moore A L
Arch Biochem Biophys. 1984 Feb 15;229(1):287-94. doi: 10.1016/0003-9861(84)90154-1.
Trifluoperazine inhibits ADP-stimulated respiration in mung bean (Phaseolus aureus) mitochondria when either NADH, malate, or succinate serve as substrates (IC50 values of 56, 59, and 55 microM, respectively). Succinate:ferricyanide oxidoreductase activity of these mitochondria was inhibited to a similar extent. The oxidation of ascorbate/TMPD was also sensitive to the phenothiazine (IC50 = 65 microM). Oxidation of exogenous NADH was inhibited by trifluoperazine even in the presence of excess EGTA [ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid] (IC50 = 60 microM), indicating an interaction with the electron transport chain rather than with the dehydrogenase itself. In contrast, substrate oxidation in Voodoo lily (Sauromatum guttatum) mitochondria was relatively insensitive to the phenothiazine. The results suggest the bc1 complex to be a major site of inhibition. The membrane potential of energized mung bean mitochondria was depressed by micromolar concentrations of trifluoperazine, suggesting an effect on the proton-pumping capability of these mitochondria. Membrane-bound and soluble ATPases were equally sensitive to trifluoperazine (IC50 of 28 microM for both), implying the site of inhibition to be on the F1. Inhibition of the soluble ATPase was not affected by EGTA, CaCl2, or exogenous calmodulin. Trifluoperazine inhibition of electron transport and phosphorylation in plant mitochondria appears to be due to an interaction with a protein of the organelle that is not calmodulin.
当以NADH、苹果酸或琥珀酸作为底物时，三氟拉嗪可抑制绿豆（Phaseolus aureus）线粒体中由二磷酸腺苷（ADP）刺激的呼吸作用（IC50值分别为56、59和55微摩尔）。这些线粒体的琥珀酸：铁氰化物氧化还原酶活性受到类似程度的抑制。抗坏血酸/四甲基对苯二胺（TMPD）的氧化也对吩噻嗪敏感（IC50 = 65微摩尔）。即使存在过量的乙二醇双（β-氨基乙基醚）-N,N'-四乙酸（EGTA），三氟拉嗪也能抑制外源NADH的氧化（IC50 = 60微摩尔），这表明其与电子传递链相互作用，而非与脱氢酶本身相互作用。相比之下，巫毒百合（Sauromatum guttatum）线粒体中的底物氧化对吩噻嗪相对不敏感。结果表明bc1复合体是主要的抑制位点。微摩尔浓度的三氟拉嗪可降低绿豆线粒体的膜电位，这表明其对这些线粒体的质子泵功能有影响。膜结合型和可溶性ATP酶对三氟拉嗪同样敏感（两者的IC50均为28微摩尔），这意味着抑制位点在F1上。可溶性ATP酶的抑制不受EGTA、氯化钙或外源钙调蛋白的影响。三氟拉嗪对植物线粒体电子传递和磷酸化的抑制作用似乎是由于其与该细胞器中一种非钙调蛋白的蛋白质相互作用所致。
