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首页> 外文期刊>Life sciences >QUANTIFICATION OF SINGLET OXYGEN FROM HEMATOPORPHYRIN DERIVATIVE BY ELECTRON SPIN RESONANCE
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QUANTIFICATION OF SINGLET OXYGEN FROM HEMATOPORPHYRIN DERIVATIVE BY ELECTRON SPIN RESONANCE

机译：电子自旋共振对血卟啉衍生物中的单氧进行定量

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The mechanism of the generation and the quantitative analysis of singlet oxygen (O-1(2)) formed by the exposure of a hematoporphyrin derivative (HpD) to light was re-evaluated by electron spin resonance (ESR) combined with 2,2,6,6,-tetramethyl-4-piperidine (TMPD). The change from TMPD to 2,2.6,6,-tetramethyl-4-piperidine-N-oxide (TAN) has been reported to depend on singlet oxygen. However, we confirmed that this reagent also reacts with superoxide anion (O-2(-)) and hydroxyl radicals (OH). Therefore, the reactions between TMPD and O-1(2), O-2(-) and OH were re-examined using a kinetic approach. We found that the generatiation of TAN was proportional to the concentration of TMPD and HpD, as well as to the duration and strength of the illumination. The generation of TAN was enhanced in the presence of deuterium oxide. The generation of TAN was not inhibited by dimethyl-sulfoxide (DMSO) or superoxide dismutase (SOD). The reaction rate between TMPD and O-1(2) was determined to be 5.0 X 10(-7) M(-1)min(-1). The generation of O-1(2) from HpD was 2.7 X 10(-7) Mmin(-1) under our conditions. The competitive reaction observed between 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and TMPD for O-2(-) or OH shows that TMPD reacts with both forms of active oxygen, but gave no ESR signal. The second-order reaction rate constant of TMPD between O-2(-) and OH was calculated as 73M(-1)s(-1) and 1.5 X 10(9)M(-1)s(-1), respectively. The photochemical generation of O-1(2) from methylene blue, another sensitzer, was also demonstrated by this method. These results show that ESR signal of TAN can be used for the highly selective monitoring of O-1(2). [References: 13]
机译：通过电子自旋共振（ESR）结合2,2，重新评估了血卟啉衍生物（HpD）暴露于光形成的单线态氧（O-1（2））的生成和定量分析机理， 6,6，-四甲基-4-哌啶（TMPD）。据报道，从TMPD到2,2.6,6，-四甲基-4-哌啶-N-氧化物（TAN）的变化取决于单线态氧。但是，我们证实该试剂还与超氧阴离子（O-2（-））和羟基自由基（OH）反应。因此，使用动力学方法重新检查了TMPD与O-1（2），O-2（-）和OH之间的反应。我们发现TAN的生成与TMPD和HpD的浓度以及照明的持续时间和强度成正比。在氧化氘存在下，TAN的生成得以增强。 TAN的生成不受二甲基亚砜（DMSO）或超氧化物歧化酶（SOD）的抑制。确定TMPD与O-1（2）之间的反应速率为5.0 X 10（-7）M（-1）min（-1）。在我们的条件下，HpD产生的O-1（2）为2.7 X 10（-7）Mmin（-1）。在5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）和TMPD之间观察到的O-2（-）或OH竞争反应表明，TMPD与两种形式的活性氧反应，但未产生ESR信号。 OPD（-2）和OH之间的TMPD二级反应速率常数分别计算为73M（-1）s（-1）和1.5 X 10（9）M（-1）s（-1） 。该方法还证明了由另一种敏化剂亚甲基蓝光化学生成O-1（2）。这些结果表明，TAN的ESR信号可用于O-1（2）的高选择性监测。 [参考：13]

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