卟啉增强辣根过氧化物酶催化的NADPH氧化反应的机制
The mechanism of potentiation of horseradish peroxidase-catalysed oxidation of NADPH by porphyrins.
作者信息
Van Steveninck J, Boegheim J P, Dubbelman T M, Van der Zee J
出版信息
Biochem J. 1987 Mar 1;242(2):611-3. doi: 10.1042/bj2420611.
Several porphyrins, including HpD (haematoporphyrin derivative), potentiate the oxidation of NADPH by horseradish peroxidase/H2O2. To elucidate the mechanism of potentiation, the following observations are relevant. During peroxidase-catalysed NADPH oxidation, O2-.(superoxide radical) is generated, as judged from superoxide dismutase-inhibitable cytochrome c reduction. This generation of O2-. is suppressed by HpD. Peroxidase-catalysed NADPH oxidation is stimulated by superoxide dismutase and by anaerobic conditions. Under anaerobic conditions HpD has no influence on peroxide-catalysed NADPH oxidation. Previous studies have shown that horseradish peroxidase is inhibited by O2-.. Thus the experimental results indicate that the potentiating effect of HpD can be explained by its ability to inhibit O2-. generation in the horseradish peroxidase/H2O2/NADPH system.
包括血卟啉衍生物（HpD）在内的几种卟啉能增强辣根过氧化物酶/H₂O₂对NADPH的氧化作用。为阐明增强作用的机制，以下观察结果具有相关性。在过氧化物酶催化的NADPH氧化过程中，从超氧化物歧化酶可抑制的细胞色素c还原判断，会产生超氧阴离子自由基（O₂⁻·）。HpD可抑制这种O₂⁻·的产生。超氧化物歧化酶和厌氧条件可刺激过氧化物酶催化的NADPH氧化。在厌氧条件下，HpD对过氧化物催化的NADPH氧化没有影响。先前的研究表明辣根过氧化物酶会被O₂⁻·抑制。因此，实验结果表明，HpD的增强作用可以用其在辣根过氧化物酶/H₂O₂/NADPH系统中抑制O₂⁻·产生的能力来解释。
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