Characterization of Endogenous and Extruded H 2 S and Small Oxoacids of Sulfur (SOS) in Cell Cultures
Year: 2021
Type: article
Abstract: This report characterizes and quantifies endogenous hydrogen sulfide (H 2 S) and small oxoacids of sulfur (SOS = HOSH, HOSOH) in a panel of cell lines including human cancer (A375 melanoma cells, HeLa cervical cells) and noncancer (HEK293 embryonic kidney cells), as well as E. coli DH5α and S. cerevisiae S288C. The methodology used is a translation of well-studied nucleophilic and electrophilic traps for cysteine and oxidized cysteines residues to target small molecular weight sulfur species; mass spectrometric analysis allows for species quantification. The observed intracellular concentrations of H 2 S and SOS vary in different cell types, from nanomolar to femtomolar, typically with H 2 S > HOSOH > HOSH. We propose the term sulfome, a subset of the metabolome, describing the nonproteinaceous metabolites of H 2 S; the sulfomic index is as a measure of the S-oxide redox status, which gives a profile of endogenous sulfur at different oxidation states. An important observation is that H 2 S and SOS were found to be continuously extruded into surrounding media against a concentration gradient, implying an active efflux process. Small molecule inhibition of several H 2 S generating enzymes suggest that SOS are not derived solely from H 2 S oxidation. Even after successful inhibition of H 2 S production, cells maintain constant efflux and repopulate H 2 S and SOS over time. This work proves that these small sulfur oxoacids are generated in cells of all types, and their efflux implies that they play a role in cell signaling and possibly other vascular physiology attributed to H 2 S.
Source: ACS Chemical Biology
Institution: Baylor University
Language: English
Topic: Sulfur Compounds in Biology
Subfield: Biochemistry
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3189009346