Fig. 3.

Mechanism of intracellular maintenance of various Cys and GSH polysulfides. (A) Schematic representation of the Cys polysulfur cycle involving CBS, CSE, and GSR for intracellular maintenance of various Cys and GSH polysulfides. (B) Regeneration of GSSH and GSSSH from GSSSG catalyzed by GSR. GSSSG (0.1 mM) was reacted with GSR (1 U/mL) and NADPH (0.2 mM) in 20 mM Tris⋅HCl buffer (pH 7.4) at room temperature for 5 min followed by incubation with 5 mM Br-bimane at 37 °C for 15 min. Shown are the (Left) LC-MS elution profile and (Right) quantitative data for the reaction. Data represent means ± SDs (n = 3).