Visible photolysis and amperometric detection of S-nitrosothiols.
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.
Daniel A
DA
Riccio
Steven T
ST
Nutz
Mark H
MH
Schoenfisch
D000818:Animals; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D004563:Electrochemistry; D009569:Nitric Oxide / Q000737:chemistry*; D009603:Nitroso Compounds / Q000032:analysis* / Q000097:blood; D010782:Photolysis; D026422:S-Nitrosoglutathione / Q000032:analysis* / Q000097:blood; D026403:S-Nitrosothiols / Q000032:analysis* / Q000097:blood; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013552:Swine
D009603:Nitroso Compounds; D026403:S-Nitrosothiols; C091665:S-nitrosoalbumin; D012710:Serum Albumin, Bovine; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C021315:S-nitrosocysteine; D003545:Cysteine