Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798, USA.
Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798, USA.
Nitric Oxide. 2018 Jul 1;77:96-105. doi: 10.1016/j.niox.2018.04.012. Epub 2018 Apr 26.
Several recent reports suggest that HNO may be produced endogenously by reaction of HS and S-nitrosoglutathione (GSNO). This hypothesis was tested using deoxymyoglobin (MbFe) to trap the expected HNO released from the target reaction, which should generate the stable HNO adduct, HNO-Mb, under anaerobic conditions. Under numerous experimental conditions, the sole globin product was NO-Mb, as characterized by absorbance, EPR, and NMR spectroscopies. Analogous reactions of GSNO with other biological reductants such as ascorbic acid, dithiothreitol, glutathione, and dithionite also yielded NO-Mb as the sole globin product; however, whereas analogous reduction of GSNO using NaBH generates HNO-Mb in high yield. Quantitative GC/MS analyses of reactions of GSNO with HS showed that the main reaction product was NO, with N produced at a comparable level to NO. Overall yield of NO is unchanged by the presence of MbFe, discounting the intermediacy of either NO or HNO in its formation. Taken together, these results argue against the generation of free HNO as a major pathway in the reactions of GSNO with HS, and instead imply some as yet uncharacterized intermediates generate the nitrogenic gases.
最近有几项报告表明，HNO 可能是由 HS 和 S-亚硝基谷胱甘肽（GSNO）的反应内生产生的。使用脱氧肌红蛋白（MbFe）来捕获预期从目标反应中释放的 HNO，在厌氧条件下应生成稳定的 HNO 加合物 HNO-Mb，从而验证了这一假设。在许多实验条件下，唯一的球蛋白产物是 NO-Mb，其特征为吸收、EPR 和 NMR 光谱。GSNO 与其他生物还原剂（如抗坏血酸、二硫苏糖醇、谷胱甘肽和连二亚硫酸盐）的类似反应也产生了 NO-Mb 作为唯一的球蛋白产物；然而，使用 NaBH 还原 GSNO 生成 HNO-Mb 的产率很高。对 GSNO 与 HS 的反应进行定量 GC/MS 分析表明，主要反应产物是 NO，N 的生成水平与 NO 相当。MbFe 的存在不会改变 NO 的总产率，从而排除了 NO 或 HNO 在其形成过程中的中间产物。综上所述，这些结果表明，GSNO 与 HS 的反应中，自由 HNO 的生成不是主要途径，而是暗示生成了一些尚未被描述的中间产物来产生氮气体。
