[Myoglobin and mitochondria: kinetics of oxymyoglobin deoxygenation in mitochondria suspension].
[Myoglobin and mitochondria: kinetics of oxymyoglobin deoxygenation in mitochondria suspension].
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[肌红蛋白和线粒体：线粒体悬浮液中氧合肌红蛋白脱氧的动力学]。
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
S. V. Tselikova
中科院分区：
文献类型：
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作者：
G. Postnikova;S. V. Tselikova
在呼吸大鼠线粒体存在的情况下，在线粒体通过仅能够转移低分子量化合物的半透膜与蛋白质溶液分离的条件下，以及在具有线粒体的MbO 2溶液中直接分离的条件下，通过电化学方法研究了鲸MbO 2脱氧的动力学（孵育培养基：15-35 mM琥珀酸盐、150 mM蔗糖、100 mM KCl、0.5 mM EGTA、5 mM KH 2 PO 4、10 mM MOPS，pH 7.4）。结果表明，在生理pO 2从MbO 2分裂O2是可能的，只有当它直接接触线粒体。脱氧速率不依赖于蛋白质浓度（[MbO 2]上的零级反应，与不存在线粒体时的一级反应相反），并且与相同条件下线粒体的耗氧速率完全一致，如极谱数据所示。利用马MbO 2（pI 7.1）、抹香鲸MbO 2（pI 8.3）、其锌络合物Zn-MbO 2（pI > 8.3）和在His残基处羧甲基化的抹香鲸MbO 2衍生物CM-MbO 2（pI 5.2）研究了MbO 2脱氧速率对线粒体和蛋白质浓度以及MbO 2分子总电荷的依赖性。MbO 2在细胞中的脱氧机制明显地激活其与线粒体膜的相互作用。结果，Mb对氧的亲和力降低了几倍，这对应于Mb解离曲线向更高pO 2值的偏移。
The kinetics of whale MbO2 deoxygenation was studied spectrophotometrically in the presence of breathing rat mitochondria under conditions when mitochondria were separated from the protein solution by a semipermeable film capable to transfer only low-molecular-weight compounds and directly in the solution of MbO2 with mitochondria (incubation medium: 15-35 mM succinate, 150 mM sucrose, 100 mM KCl, 0.5 mM EGTA, 5 mM KH2PO4, 10 mM MOPS, pH 7.4). It was shown that the splitting of O2 from MbO2 at physiological pO2 is possible only if it directly contacts mitohondria. The deoxygenation rate does not depend on the protein concentration (zero order on [MbO2] as opposite to the first order reaction in the absence of mitochondria) and completely coincides with the rate of oxygen consumption by mitochondria under the same conditions, as indicated by the polarographic data. The dependence of the MbO2 deoxygenation rate on the concentration of mitochondria and the protein, and on the total charge of the MbO2 molecule was studied using horse MbO2 (pI 7.1), sperm whale MbO2 (pI 8.3), its zinc complex, Zn-MbO2 (pI > 8.3), and the sperm whale MbO2 derivative carboxymethylated at His residues, CM-MbO2 (pI 5.2). The mechanism of MbO2 deoxygenation in the cell obviously actuates its interplay with the mitochondrial membrane. As a result, the affinity of Mb to oxygen decreases several times, which corresponds to a shift of the Mb dissociation curve to higher pO2 values.