The oxidation of cysteine-containing peptides caused by perfluoroalkane sulfonyl fluorides

Zhe Jin, Quan He, Haiwei Luo, Yuanjiang Pan, Cuirong Sun*, Zongwei CAI

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Perfluorooctane sulfonyl fluoride (PFOSF) is the precursor of many fluorochemicals that are ubiquitous in the environment. However, its distribution and toxicology are rarely studied. In this work, the oxidability of PFOSF was found. PFOSF can accelerate oxidation of glutathione (GSH) to its oxidized form GSSG, and itself is reduced to a sulfinic acid. The yielded sulfinic acid was prepared and identified with high resolution mass spectrometry and NMR. Similar redox reactions were observed for PFOSF's short chain alternatives. The reduction potentials of perfluoroalkane sulfonyl fluorides (PFASFs) were determined to be −2.13 V vs. SCE with cyclic voltammetry, further demonstrating their oxidability. The peptide mixtures of GSH plus another cysteine-containing peptide were also oxidized by PFASFs to GSSG and an asymmetric disulfide GS-S-PEP. A single short-sequence PEP-SH could be oxidized to the symmetric disulfide PEP-S-S-PEP as the final product. In vitro experiments were carried out by adding PFASFs into rat liver S9 fractions. The turnover ratio of PFASFs were calculated to be about 4–10% by quantification of sulfinic acid with LC–MS/MS. Our work illustrates one of the potential metabolic pathways of PFASFs and demonstrates the oxidation of PEP-SHs by PFASFs, thus providing a preliminary exploration in the toxicology of these fluorochemicals.

Original languageEnglish
Article number121564
JournalJournal of Hazardous Materials
Volume385
DOIs
Publication statusPublished - 5 Mar 2020

Scopus Subject Areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • GSH
  • LC–MS
  • Liver S9
  • Oxidation toxicology
  • PFASFs

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