氧气逐步单电子还原为水产生的活性氧(ROS)在化学和生化上与反应性硫化物(RSS)相似,该硫化物是由硫化氢单电子氧化为元素硫衍生的。ROS和RSS都是内源性产生的,并通过蛋白质硫醇发出信号。鉴于ROS和RSS之间的相似性,我们想知道现有的测量前者的方法是否也能检测到后者。这里,我们比较了五种常见ROS方法的ROS与RSS敏感性:氧化还原敏感的绿色荧光蛋白(roGFP),2\',7\'-二氢二氯荧光素,MitoSoxRed,双色红,和安培电极。所有方法都检测到RSS,或更多,对RSS比对ROS敏感。roGFP,可以说是ROS测量的“黄金标准”,对混合多硫化物H2Sn(n=1-8)的敏感性比对H2O2高200倍以上。这些发现表明,RSS在细胞内信号传导中可能比以前认识到的更为普遍,并且ROS的贡献可能被高估了。这一结论进一步得到了以下观察结果的支持:估计的每日硫代谢和ROS产生大约相等,以及自生命起源以来就存在RSS和抗氧化机制的事实。近40亿年前,早在6亿年前环境氧气上升之前。尽管ROS被认为是最具生物学相关性的氧化剂,我们的结果质疑这个范式。我们还预计我们的发现将把注意力转向新型和临床相关的抗(RSS)氧化剂的开发。
Stepwise one-electron reduction of oxygen to water produces reactive oxygen species (ROS) that are chemically and biochemically similar to reactive
sulfide species (RSS) derived from one-electron oxidations of hydrogen
sulfide to elemental sulfur. Both ROS and RSS are endogenously generated and signal via protein thiols. Given the similarities between ROS and RSS, we wondered whether extant methods for measuring the former would also detect the latter. Here, we compared ROS to RSS sensitivity of five common ROS methods: redox-sensitive green fluorescent protein (roGFP), 2\', 7\'-dihydrodichlorofluorescein, MitoSox Red, Amplex Red, and amperometric electrodes. All methods detected RSS and were as, or more, sensitive to RSS than to ROS. roGFP, arguably the \"gold standard\" for ROS measurement, was more than 200-fold more sensitive to the mixed polysulfide H2Sn(n = 1-8) than to H2O2 These findings suggest that RSS may be far more prevalent in intracellular signaling than previously appreciated and that the contribution of ROS may be overestimated. This conclusion is further supported by the observation that estimated daily sulfur metabolism and ROS production are approximately equal and the fact that both RSS and antioxidant mechanisms have been present since the origin of life, nearly 4 billion years ago, long before the rise in environmental oxygen 600 million years ago. Although ROS are assumed to be the most biologically relevant oxidants, our results question this paradigm. We also anticipate our findings will direct attention toward development of novel and clinically relevant anti-(RSS)-oxidants.