Curtis W E, Muldrow M E, Parker N B, Barkley R, Linas S L, Repine J E
Department of Medicine, Webb-Waring Lung Institute, University of Colorado Health Sciences Center, Denver.
Proc Natl Acad Sci U S A. 1988 May;85(10):3422-5. doi: 10.1073/pnas.85.10.3422.
We hypothesized that measurement of a specific product from reaction of N,N'-dimethylthiourea (Me2TU) and H2O2 would provide a good indication of the H2O2 scavenging and protection seen after addition of Me2TU to biological systems. We found that addition of H2O2 to Me2TU yielded a single stable product, Me2TU dioxide. Me2TU dioxide formation correlated with Me2TU consumption as a function of added H2O2 concentration and was prevented by simultaneous addition of catalase (but not boiled catalase), superoxide dismutase, dimethyl sulfoxide, mannitol, or sodium benzoate. Me2TU dioxide formation, Me2TU consumption, and H2O2 concentration increases occurred in mixtures containing phorbol 12-myristate 13-acetate (PMA) and normal human neutrophils but not in mixtures containing PMA and neutrophils from patients with chronic granulomatous disease or in mixtures containing PMA and normal neutrophils and catalase. Me2TU dioxide formation also occurred in isolated rat lungs perfused with Me2TU and H2O2 but not in lungs perfused with Me2TU and elastase, histamine, or oleic acid. In contrast, Me2TU dioxide formation did not occur after exposure of Me2TU to 60Co-generated hydroxyl radical or hypochlorous acid in the presence of catalase. The results indicate that reaction of Me2TU with H2O2 selectively forms Me2TU dioxide and that measuring Me2TU dioxide formation from Me2TU may be useful for assessing the presence and significance of H2O2 in biological systems.
我们推测，通过测量N，N'-二甲基硫脲（Me2TU）与过氧化氢（H2O2）反应产生的特定产物，能够很好地表明在向生物系统中添加Me2TU后所观察到的H2O2清除和保护作用。我们发现，向Me2TU中添加H2O2会产生一种单一的稳定产物——二甲基硫脲二氧化物。二甲基硫脲二氧化物的形成与Me2TU的消耗相关，是添加的H2O2浓度的函数，并且同时添加过氧化氢酶（而非煮沸的过氧化氢酶）、超氧化物歧化酶、二甲基亚砜、甘露醇或苯甲酸钠可阻止其形成。在含有佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）和正常人中性粒细胞的混合物中会发生二甲基硫脲二氧化物的形成、Me2TU的消耗以及H2O2浓度的增加，但在含有PMA和慢性肉芽肿病患者的中性粒细胞的混合物中，或在含有PMA、正常中性粒细胞和过氧化氢酶的混合物中则不会发生。在灌注了Me2TU和H2O2的离体大鼠肺中也会发生二甲基硫脲二氧化物的形成，但在灌注了Me2TU和弹性蛋白酶、组胺或油酸的肺中则不会发生。相比之下，在过氧化氢酶存在下，将Me2TU暴露于60Co产生的羟基自由基或次氯酸后，不会发生二甲基硫脲二氧化物的形成。结果表明，Me2TU与H2O2反应选择性地形成二甲基硫脲二氧化物，并且测量由Me2TU形成的二甲基硫脲二氧化物可能有助于评估生物系统中H2O2的存在及其重要性。
