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首页> 外文期刊>The Journal of Nutritional Biochemistry >Theaflavins inhibit the ATP synthase and the respiratory chain without increasing superoxide production.
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Theaflavins inhibit the ATP synthase and the respiratory chain without increasing superoxide production.

机译：茶黄素抑制ATP合酶和呼吸链而不增加超氧化物的产生。

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摘要

Four dietary polyphenols, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate and theaflavin-3,3'-digallate (TF3), have been isolated from black tea, and their effects on oxidative phosphorylation and superoxide production in a model system (Escherichia coli) have been examined. The esterified theaflavins were all potent inhibitors of the membrane-bound adenosine triphosphate (ATP) synthase, inhibiting at least 90% of the activity, with IC50 values in the range of 10-20 micro M. ATP-driven proton translocation was inhibited in a similar fashion, as was the purified F1-ATPase, indicating that the primary site of inhibition was in the F1 sector. Computer modeling studies supported this interpretation. All four theaflavins were also inhibitory towards the electron transport chain, whether through complex I (NDH-1) or the alternative NADH dehydrogenase (NDH-2). Inhibition of NDH-1 by TF3 appeared to be competitive with respect to NADH, and this was supported by computer modeling studies. Rates of superoxide production during NADH oxidation by each dehydrogenase were measured. Superoxide production was completely eliminated in the presence of about 15 micro M TF3, suggesting that inhibition of the respiratory chain by theaflavins does not contribute to superoxide production.
机译：从红茶中分离出四种膳食多酚茶黄素，茶黄素-3-没食子酸酯，茶黄素3'-没食子酸酯和茶黄素-3,3'-二没食子酸酯（TF3），它们在模型中对氧化磷酸化和超氧化物产生具有影响系统（大肠杆菌）已经过检查。酯化的茶黄素都是膜结合三磷酸腺苷（ATP）合酶的有效抑制剂，可抑制至少90％的活性，IC <50> 值在10-20 micro M范围内。驱动的质子易位受到抑制，纯化的F 1 -ATPase也是如此，这表明抑制的主要位点在F 1 区域。计算机建模研究支持这种解释。无论通过复合物I（NDH-1）还是通过替代的NADH脱氢酶（NDH-2），所有四个茶黄素都对电子传输链具有抑制作用。 TF3对NDH-1的抑制作用似乎相对于NADH具有竞争性，这得到计算机模型研究的支持。测量了在NADH被每种脱氢酶氧化过程中超氧化物的产生速率。在约15 micro M TF3的存在下，完全消除了超氧化物的产生，这表明茶黄素对呼吸链的抑制作用无助于超氧化物的产生。

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