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首页> 外文期刊>Biochemistry >Myoglobin and mitochondria: Oxymyoglobin interacts with mitochondrial membrane during deoxygenation
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Myoglobin and mitochondria: Oxymyoglobin interacts with mitochondrial membrane during deoxygenation

机译：肌红蛋白和线粒体：氧合肌红蛋白在脱氧过程中与线粒体膜相互作用

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The rates of oxygen uptake by rat liver mitochondria (MC) (native coupled, freshly frozen, and uncoupled by FCCP) have been measured polarographically in the absence (V0) or presence (V1) of 0.11-0.25 mM sperm whale MbO2. Under the same standard conditions, the rate of sperm whale MbO2 deoxygenation (V2) has been studied spectrophotometrically in the presence of respiring MC. For freshly frozen MC, the dependence of V1 and V2 on the overall charge of MbO2 has been investigated at pH 5.6-7.6, and the influence of other differently charged proteins (apomyoglobin, egg lysozyme, lactalbumin, and BSA) has been studied at pH 7.4. It is shown that the rate of mitochondrial respiration in the presence of MbO2 increases by 10-30% (V1 > V0). No myoglobin effect is observed for FCCP-uncoupled MC (Vmax does not change). The rate of MbO2 deoxygenation is equal to the rate of oxygen uptake by mitochondria (V2/V1 1 at pH 7.2-7.5). At varying pH < 7.2, the V2 values become markedly higher than V1, evidently due to the increased MbO2 positive charge and its stronger interaction with negatively charged mitochondrial membrane. At pH 7.4, on the contrary, V2 is twice lower than V1 in the case of negatively charged CM-MbO2 (pI 5.2), which has carboxymethylated histidines. Positively charged lysozyme (pI 11) strongly inhibits MbO2 deoxygenation (V2) without affecting oxygen uptake by MC (V0 and V1). At the same time, apomyoglobin (pI 8.5), which is structurally very similar to the holoprotein, and both negatively charged lactalbumin (pI 4.4) and BSA (pI 4.7) have no substantial influence on V2 and V1. The MC membrane evidently has no specific sites for the interaction with myoglobin. Rather, the protein contacts with phospholipids of the outer membrane during MbO2 deoxygenation, and electrostatic interactions are of great importance for this process. [PUBLICATION ABSTRACT]
机译：在没有（V0）或有（V1）0.11-0.25 mM抹香鲸MbO2的条件下，通过极谱法测量了大鼠肝线粒体（MC）（天然偶联，新鲜冷冻和未偶联FCCP）的氧气吸收率。在相同的标准条件下，已经在呼吸性MC存在下用分光光度法研究了抹香鲸MbO2的脱氧速率（V2）。对于新鲜冷冻的MC，已在pH 5.6-7.6下研究了V1和V2对MbO2总电荷的依赖性，并且在pH值下研究了其他带电不同的蛋白质（肌红蛋白，卵溶菌酶，乳清蛋白和BSA）的影响。 7.4。结果表明，在存在MbO2的情况下，线粒体呼吸的速率增加了10％至30％（V1> V0）。对于未偶联FCCP的MC，未观察到肌红蛋白效应（Vmax不变）。 MbO2脱氧的速率等于线粒体吸收的氧气的速率（pH值为7.2-7.5时为V2 / V1.1）。在变化的pH <7.2时，V2值变得明显高于V1，这显然是由于MbO2正电荷的增加及其与带负电荷的线粒体膜的较强相互作用。相反，在pH 7.4的情况下，对于带羧基甲基化组氨酸的CM-MbO2带负电（pI 5.2），V2比V1低两倍。带正电荷的溶菌酶（pI 11）强烈抑制MbO2脱氧（V2），而不会影响MC吸收的氧气（V0和V1）。同时，结构上与全蛋白非常相似的apomyoglobin（pI 8.5），带负电荷的乳清蛋白（pI 4.4）和BSA（pI 4.7）对V2和V1均无实质性影响。 MC膜显然没有与肌红蛋白相互作用的特定位点。而是，蛋白质在MbO2脱氧过程中与外膜的磷脂接触，静电相互作用对该过程非常重要。 [出版物摘要]

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