S-Nitrosothiols (RSNOs) such as S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylpenicillamine (SNAP) are susceptible to decomposition by stimuli including heat, light, and trace metal ions. Using stepwise isothermal thermogravimetric analysis (TGA), we observed that NO-forming homolytic cleavage of the S-N bond occurs at 134.7 ± 0.8 °C in GSNO and 132.8 ± 0.9 °C in SNAP, contrasting with the value of 150 °C that has been previously reported for both RSNOs. Using mass spectrometry (MS), nuclear magnetic resonance (NMR), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), we analyzed the decomposition products from TGA experiments. The organic product of GSNO decomposition was glutathione disulfide, while SNAP decomposed to form N-acetylpenicillamine disulfide as well as other products, including tri- and tetrasulfides. In addition, we assessed the relative solution stabilities of GSNO and SNAP under common laboratory conditions, which include variable temperature, pH, and light exposure with rigorous exclusion of trace metal ions by chelation. GSNO exhibited greater stability than SNAP over a 7-day period except in one instance. Both RSNOs demonstrated an inverse relationship between solution stability and temperature, with refrigeration considerably extending shelf life. A decrease in pH from 7.4 to 5.0 also enhanced the stability of both RSNOs. A further decrease in pH from 5.0 to 3.0 resulted in decreased stability for both RSNOs, and is notably the only occasion in which SNAP proved more stable than GSNO. After 1 h of exposure to overhead fluorescent lighting, both RSNOs displayed high susceptibility to light-induced decomposition. After 7 h, GSNO and SNAP decomposed 19.3 ± 0.5% and 30 ± 2%, respectively.

中文翻译：

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在常见的实验室条件下，S-亚硝基谷胱甘肽比S-亚硝基-N-乙酰青霉胺具有更高的稳定性：一项比较稳定性研究。

S-亚硝基巯基硫醚（RSNO），例如S-亚硝基谷胱甘肽（GSNO）和S-亚硝基-N-乙酰青霉胺（SNAP）易受刺激分解，包括热，光和痕量金属离子。使用逐步等温热重分析（TGA），我们观察到SNNO的NO形成均质裂解发生在GSNO中为134.7±0.8°C，在SNAP中为132.8±0.9°C，而之前的值为150°C先前针对两个RSNO进行过报告。使用质谱（MS），核磁共振（NMR）和衰减全反射傅里叶变换红外光谱（ATR-FTIR），我们分析了TGA实验的分解产物。GSNO分解的有机产物是谷胱甘肽二硫化物，而SNAP分解形成N-乙酰青霉胺二硫化物以及其他产物，包括三硫化物和四硫化物。此外，我们评估了普通实验室条件下GSNO和SNAP的相对溶液稳定性，这些条件包括可变温度，pH值以及通过螯合严格排除痕量金属离子的光照。GSNO在7天的时间内显示出比SNAP更高的稳定性，除了一种情况外。两种RSNO均显示出溶液稳定性和温度之间呈反比关系，冷藏显着延长了保质期。pH从7.4降低到5.0也增强了两种RSNO的稳定性。pH值进一步从5.0降低到3.0导致两种RSNO的稳定性下降，这是SNAP证明比GSNO更稳定的唯一情况。暴露于头顶荧光灯1小时后，两种RSNO均表现出对光诱导分解的高度敏感性。7小时后，GSNO和SNAP分别分解了19.3±0.5％和30±2％。