Synthesis of l -cysteine derivatives containing stable sulfur isotopes and application of this synthesis to reactive sulfur metabolome

N-Acetyl Cysteine Functions as a Fast-Acting Antioxidant by Triggering Intracellular H2S and Sulfane Sulfur Production

“…as induced in the liver by paracetamol overdose, a major indication for the clinical use of NAC (Green et al, 2013). The tracing of 34 S-labeled NAC in Cys/Met-deprived cells confirmed its incorporation into newly synthesized GSH (Ono et al, 2017). Although it makes perfect sense that cells use NAC-derived Cys for GSH biosynthesis when the need for Cys is not matched by its supply, the question remains if the biosynthetic use of Cys generally or typically explains the effects afforded by NAC.…”

Enhanced Cellular Polysulfides Negatively Regulate TLR4 Signaling and Mitigate Lethal Endotoxin Shock

“…We performed LC-MS/MS-based sulfur metabolomic analysis to quantify various sulfur species present in cells (Akaike et al, 2017;Ida et al, 2014;Kunikata et al, 2017;Numakura et al, 2017;Ono et al, 2017). In brief, cells treated under certain conditions were washed once with phosphate-buffered saline (PBS) and were harvested with a methanol solution containing 5 mM HPE-IAM.…”

“…NAC polysulfides were prepared by reacting NAC with sulfide in the presence of certain oxidants, similar to the protocol used for preparation of cysteine polysulfides as reported previously (Akaike et al, 2017;Ida et al, 2014;Ono et al, 2017). In brief, NAC (60 mM) was reacted with 60 mM NaNO 2 in H 2 O at 37 C for 5 min, followed by addition of NaHS (final concentration, 45 mM) and formic acid (final concentration, 0.2%) and another incubation at 37 C for 15 min.…”

“…For precise quantification, isotope-labeled HPE-AM adducts were spiked into samples. HPE-AM adducts of cysteine, GSH, their hydropersulfides/polysulfides, and H 2 S were prepared as described previously (Akaike et al, 2017;Ida et al, 2014;Ono et al, 2017). The same protocol was applied to preparation of NAC adducts.…”

“…Cysteine persulfide (CysSSH) and cysteine polysulfides (CysS[S] n H, n > 2) are cysteine derivatives having sulfane sulfur atoms bound to cysteine thiol (Fukuto et al, 2018;Ida et al, 2014;Ono et al, 2014;Sawa et al, 2018). Accumulating evidence has suggested that cysteine persulfides/polysulfides are abundant in prokaryotes and eukaryotes in diverse forms such as monomeric amino acid hydropersulfides/polysulfides (CysSSH, CysS[S] n H), reduced L-glutathione (GSH) hydropersulfides/polysulfides (GS[S] n H), and protein persulfide/polysulfide residues (Akaike et al, 2017;Ida et al, 2014;Kunikata et al, 2017;Numakura et al, 2017;Ono et al, 2017;Peng et al, 2017). Hydropersulfides/polysulfides are highly potent antioxidants and hence protect cells from injury induced by reactive oxygen species (ROS) (Ida et al, 2014;Kunikata et al, 2017).…”