School of Pharmacy, National Defense Medical Center, Taipei, Taiwan ROC.
Free Radic Res. 2012 Oct;46(10):1190-200. doi: 10.3109/10715762.2012.698010. Epub 2012 Jun 21.
To study oxidative stress in biological systems, chemical compounds capable of producing free radicals have been widely used. Here, we compared two free-radical generators, 3-morpholinosydnonimine (SIN-1) and 2,2'-azo-bis(2-amidinopropane) hydrochloride (AAPH), by measuring the thiol oxidation kinetics of various thiols. We found that SIN-1 is > 30 times potent in causing thiol oxidation than AAPH. Kinetic simulations revealed that in the SIN-1 system (0.1 mM), superoxide, nitrogen dioxide and carbonate radicals are the major reactive species which, in combination, induce ∼50% of thiol molecules to undergo one-electron oxidation, thereby forming the thiyl radical which propagates further thiol oxidation by direct coupling with thiolates. Similarly, the alkyl peroxyl radical derived from AAPH (3 mM) initiates comparable extent of one-electron oxidation and formation of the thiyl radical. In conclusion, our study provides experimental and theoretical evidence that SIN-1 is mainly an one-electron oxidizing agent that can be functionally mimicked by AAPH.
为了研究生物体系中的氧化应激，人们广泛使用能够产生自由基的化合物。在这里，我们通过测量各种巯基的氧化动力学，比较了两种自由基发生器：3-吗啉代-sydnonimine（SIN-1）和 2,2'-偶氮双（2-脒基丙烷）盐酸盐（AAPH）。我们发现，SIN-1 引起巯基氧化的效力比 AAPH 强>30 倍。动力学模拟表明，在 SIN-1 体系（0.1 mM）中，超氧自由基、二氧化氮自由基和碳酸根自由基是主要的活性物质，它们共同诱导约 50%的巯基分子发生单电子氧化，从而形成硫自由基，通过与硫醇盐直接偶联进一步引发巯基氧化。类似地，AAPH（3 mM）衍生的烷基过氧自由基引发相当程度的单电子氧化和硫自由基的形成。总之，我们的研究提供了实验和理论证据，表明 SIN-1 主要是一种单电子氧化剂，可以被 AAPH 功能模拟。
