Anal Chem. 2012 Jan 17;84(2):851-6. doi: 10.1021/ac2031805. Epub 2011 Dec 27.
The concentration of S-nitrosothiols (RSNOs), endogenous transporters of the signaling molecule nitric oxide (NO), fluctuate greatly in physiology often as a function of disease state. RSNOs may be measured indirectly by cleaving the S-N bond and monitoring the liberated NO. While ultraviolet photolysis and reductive-based cleavage both decompose RSNOs to NO, poor selectivity and the need for additional reagents preclude their utility clinically. Herein, we report the coupling of visible photolysis (i.e., 500-550 nm) and amperometric NO detection to quantify RSNOs with greater selectivity and sensitivity. Enhanced sensitivity (up to 1.56 nA μM(-1)) and lowered theoretical detection limits (down to 30 nM) were achieved for low molecular weight RSNOs (i.e., S-nitrosoglutathione, S-nitrosocysteine) by tuning the irradiation exposure. Detection of nitrosated proteins (i.e., S-nitrosoalbumin) was also possible, albeit at a decreased sensitivity (0.11 nA μM(-1)). This detection scheme was used to measure RSNOs in plasma and illustrate the potential of this method for future physiological studies.
S-亚硝基硫醇（RSNOs）是信号分子一氧化氮（NO）的内源性转运体，其浓度在生理上波动很大，通常与疾病状态有关。RSNOs 可以通过裂解 S-N 键并监测释放的 NO 来间接测量。虽然紫外线光解和基于还原的裂解都能将 RSNOs 分解为 NO，但较差的选择性和对额外试剂的需求限制了它们在临床上的应用。在此，我们报告了可见光光解（即 500-550nm）和安培检测的偶联，以实现对 RSNOs 的更高选择性和灵敏度的定量。通过调整辐照暴露，实现了对低分子量 RSNOs（即 S-亚硝基谷胱甘肽、S-亚硝基半胱氨酸）的增强灵敏度（高达 1.56nAμM-1）和降低的理论检测限（低至 30nM）。还可以检测亚硝化蛋白（即 S-亚硝基白蛋白），尽管灵敏度降低（0.11nAμM-1）。该检测方案用于测量血浆中的 RSNOs，并说明了该方法在未来生理研究中的潜力。
