Simultaneous and sensitive quantification of protein and low molecular weight persulfides, polysulfides and H<sub>2</sub>S in biological samples.

Miljkovic, Jan Lj; Burger, Nils; Yu, Chak Shun; Harkiss, Alexander H; Warrington, Stefan; Caldwell, Stuart T; Jones, Scott A; Lee, Jordan J et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

H<sub>2</sub>S reversibly modifies low molecular weight (L<sub>MW</sub>SH) and protein (PrSH) thiols to form persulfides (RSS<sup>-</sup>) and polysulfides (RS(S)<sub>n</sub>S<sup>-</sup>) for antioxidant defence and regulation of activity. However, our understanding of the biological significance of these processes is hampered by our inability to quantify these modifications. We develop a sensitive LC-MS/MS procedure that traps the sulfur atom of H<sub>2</sub>S, and the terminal sulfur atom of RSS<sup>-</sup> and RS(S)<sub>n</sub>S<sup>-</sup> as diagnostic products in biological samples. In parallel, we also trap internal S atoms of RS(S)<sub>n</sub>S<sup>-</sup>, enabling quantification of H<sub>2</sub>S, RSS<sup>-</sup> and RS(S)<sub>n</sub>S<sup>-</sup>. L<sub>MW</sub>S(S)<sub>n</sub>S<sup>-</sup> and PrS(S)<sub>n</sub>S<sup>-</sup> are determined simultaneously in the same sample. Glutathione (GSH) is the most abundant L<sub>MW</sub>SH so we develop an orthogonal approach to quantify GSS<sup>-</sup>, enabling corroboration of L<sub>MW</sub>SS<sup>-</sup> measurements by sulfur atom trapping. We demonstrate in systems from proteins to ex vivo tissues how these approaches enable exploration of persulfidation in biological systems.

Medical subject headings