Fig. 2From: Emerging pharmacological tools to control hydrogen sulfide signaling in critical illnessPathways of H2S oxidation. H2S is serially oxidized to generate GSSH by sulfide: quinone oxidoreductase (SQR). Sulfur dioxygenase (ETHE1 or SDO) catabolizes GSSH to produce sulfite which is further catabolized to produce thiosulfate and sulfate by catalytic activity of thiosulfate sulfurtransferase (TST or rhodanese) and sulfite oxidase (SO), respectively. H2S can be oxidized by the heme iron-mediated oxidation or auto-oxidation to produce thiosulfate or polysulfide. The main oxidative product is thiosulfate or polysulfide when sulfide/O2 level is low or high, respectivelyBack to article page