THE ROLE OF INTRAMITOCHONDRIAL CA2+ IN THE REGULATION OF OXIDATIVE-PHOSPHORYLATION IN MAMMALIAN-TISSUES
THE ROLE OF INTRAMITOCHONDRIAL CA2+ IN THE REGULATION OF OXIDATIVE-PHOSPHORYLATION IN MAMMALIAN-TISSUES
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DOI：
10.1042/bst0210793
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发表时间：
1993-08-01
影响因子：
3.9
通讯作者：
DENTON, RM
中科院分区：
文献类型：
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作者：
MCCORMACK, JG;DENTON, RM
在哺乳动物组织中氧化磷酸化的整个过程中，允许呼吸通道的氧化以产生ATP形式的有用能量。它涉及通过线粒体酶形成LAD 11和还原性f1蛋白，以及随后通过线粒体内膜中的分子氧氧化它们11-41。最后一个过程是C。由呼吸链分解的氧化还原以逐步的方式发生，因此来自黄素蛋白的NAI的电子中可用的氧化还原能量可以通过将质子从内膜的基质面泵送到细胞质侧来利用。所得到的质子动力学梯度用于驱动ATI的合成。而ATP-合成酶反应保持远离平衡，使得随后的A7 ′ P水解可以为细胞提供有用的填充能量。与任何酶促过程一样，氧化磷酸化的净速率可以通过底物供应、终产物抑制和相关酶的活性来调节。因此，线粒体氧化还原状态、ATI '/AI）P. PI比率发生变化。质子动力梯度、氧的供应和呼吸链组分的活性都可能起作用。每种机制所施加的控制作用根据特定的细胞环境而变化。譬如说在“静止”细胞条件下，可能的是，A 'I' P的使用将处于最低水平。ATI ′/AI）1 ′。1 '，比率将达到高的稳态水平，因此对质子动力梯度施加反馈抑制影响。这将建立起来，所以将有一个类似的效果
I he overall process of oxidative phosphorylation in m; ininialian tissues allows the oxidation of respiratory friels to produce useful energy in the form of ATP. It involves the formation of LAD1 1 and reducrd f1; ivoproteins by mitochondrial dehydrogenases,; ind their subsequent oxidation by molecular oxygen in the niitochondrial inner membrane 11-41. The latter process is c. atalysed by the respiratory chain iind occurs in a stepwise manner, so that the redox energy available in the electrons from NAI) I I; id from flavoproteins can he harnessed by pumping protons from the matrix face of the inner mrmbrane to the cytoplasmic side. l’he resultant protonmotive gr; idient is used to drive the synthesis of ATI’. while the ATP-synthetase reaction is held far from equilibrium so that subsequent A7’P hydrolysis can provide usefill energy for the cell. As witti any enzymic-based process, the net rate of oxidative phosphorylation can be regulated hy substrate supply, by end-product inhibition, and by the activities of the enzymes involved. Thus, chmges in the mitochondrial redox status, the ATI’/AI) P. PI ratio. the protonmotive gradient, the supply of oxygen, and the activity of components of the respiratory chain, may all play; I role [1-41, The sh; ire of control that is exerted by each mechanism varies according to the particular cellular circumstances. For instance. under ‘resting’cellular conditions, it is probable that, as A ‘I’P use will be at a minimurn. the ATI’/AI) 1’. 1’, ratio will achieve a high steady-state level and so exert a feedback inhibitory influence on the protonmotive gradient. This will then build up, arid so will have a similar effect