Calcium-Induced Mitochondrial Permeability Transitions: Parameters of Ca2+ Ion Interactions with Mitochondria and Effects of Oxidative Agents
Calcium-Induced Mitochondrial Permeability Transitions: Parameters of Ca2+ Ion Interactions with Mitochondria and Effects of Oxidative Agents
复制标题
DOI：
10.1007/s00232-017-9953-2
复制
发表时间：
2017-04-01
影响因子：
2.4
通讯作者：
Zavodnik, Ilya B.
中科院分区：
文献类型：
--
作者：
Golovach, Nina G.;Cheshchevik, Vitali T.;Zavodnik, Ilya B.
我们评估了Ca 2+诱导的线粒体渗透性转换（MPT）孔形成的参数，Ca 2+结合常数，化学计量，活化能，以及氧化剂，叔丁基过氧化氢（tBHP）和次氯酸（HOCl）对大鼠肝线粒体Ca 2+介导的过程的影响。根据线粒体膜电位速率与Ca ~（2+）浓度关系的Hill图，我们确定了Ca ~（2+）与线粒体位点相互作用的顺序，n = 3，表观Kd = 60 +/-12 A μ M。我们还发现，Ca 2+与线粒体相互作用的表观米氏常数K-m等于75 +/- 20 A μ M，而在300 A μ M tBHP存在下为120 +/- 20 A μ M。使用Arrhenius图的温度依赖性的表观线粒体肿胀速率在不同的Ca 2+浓度，我们计算的MPT过程的活化能。Δ E-a在低于Arrhenius曲线的折点（30-34 ℃）的温度下为130 +/-20 kJ/mol，在较高温度下为50 +/-9 kJ/mol。Ca ~（2+）离子可引起线粒体NADH快速耗竭和膜去极化。环孢菌素A抑制钙依赖性线粒体去极化和镁离子衰减的电位耗散的孔形成的预防。tBHP（10-150 μ M）剂量依赖性地增加MPT开放率，而HOCl对MPT的影响依赖于HOCl/Ca ~（2+）比值。在溶胀反应中，tBHP与线粒体相互作用的表观K-m被发现为K-m = 11 +/-3 A μ M。本研究为MPT过程中三种钙离子以高亲和力与线粒体位点相互作用提供了证据。Ca 2+诱导的MPT孔形成由于线粒体膜蛋白变性导致膜电位耗散。不同机制的氧化剂，tBHP和HOCl，降低线粒体膜电位和氧化线粒体NADH在EDTA-自由的培养基中，并有影响的Ca 2+诱导的MPT的发病。
We evaluated the parameters of Ca2+-induced mitochondrial permeability transition (MPT) pore formations, Ca2+ binding constants, stoichiometry, energy of activation, and the effect of oxidative agents, tert-butyl hydroperoxide (tBHP), and hypochlorous acid (HOCl), on Ca2+ -mediated process in rat liver mitochondria. From the Hill plot of the dependence of MPT rate on Ca2+ concentration, we determined the order of interaction of Ca2+ ions with the mitochondrial sites, n = 3, and the apparent K-d = 60 +/- 12 A mu M. We also found the apparent Michaelis-Menten constant, K-m, for Ca2+ interactions with mitochondria to be equal to 75 +/- 20 A mu M, whereas that in the presence of 300 A mu M tBHP was 120 +/- 20 A mu M. Using the Arrhenius plots of the temperature dependences of apparent mitochondrial swelling rate at various Ca2+ concentrations, we calculated the activation energy of the MPT process. Delta E-a was 130 +/- 20 kJ/mol at temperatures below the break point of the Arrhenius plot (30-34 A degrees C) and 50 +/- 9 kJ/mol at higher temperatures. Ca2+ ions induced rapid mitochondrial NADH depletion and membrane depolarization. Prevention of the pore formation by cyclosporin A inhibited Ca2+-dependent mitochondrial depolarization and Mg2+ ions attenuated the potential dissipation. tBHP (10-150 A mu M) dose-dependently enhanced the rate of MPT opening, whereas the effect of HOCl on MPT depended on the ratio of HOCl/Ca2+. The apparent K-m of tBHP interaction with mitochondria in the swelling reaction was found to be K-m = 11 +/- 3 A mu M. The present study provides evidence that three calcium ions interact with mitochondrial site with high affinity during MPT. Ca2+-induced MPT pore formations due to mitochondrial membrane protein denaturation resulted in membrane potential dissipation. Oxidants with different mechanisms, tBHP and HOCl, reduced mitochondrial membrane potential and oxidized mitochondrial NADH in EDTA-free medium and had an effect on Ca2+-induced MPT onset.