Cyclic 5-Membered Disulfides Are Not Selective Substrates of Thioredoxin Reductase, but Are Opened Nonspecifically

17 January 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


The cyclic five-membered disulfide 1,2-dithiolane has been used as the key element in numerous chemical biology probes. Contradictory views of this disulfide populate the literature: some reports describe it as being nonspecifically reduced, others as a highly specific substrate for thioredoxin reductase (TrxR). We here show that 1,2-dithiolane probes are nonspecifically reduced by a broad range of thiol reductants and redox-active proteins, and that their cellular performance is barely affected by TrxR inhibition or knockout. We conclude that inhibitor screenings and "TRFS" probes that have used 1,2-dithiolanes as TrxRselective substrates should be treated with caution, and may need re-evaluation. Understanding 1,2-dithiolanes’ behaviour needs consideration of probe localisation and environmentdependent fluorescence, reduction-independent ring-opening polymerisation, thiol-dependent cellular uptake, and caution when applying thiophilic inhibitors. We present an approach controlling against assay misinterpretation with reducible probes, to ensure that future TrxR-targeted designs are robustly evaluated for selectivity, and to better orient future research.


disulfide moiety
redox activity
redox biology
redox biochemistry
probe candidate drug targets
Thioredoxin Reductase Inhibitors
thioredoxin reductase activity
thioredoxin reductase
Thioredoxin Redox Properties
thioredoxin superfamily enzymes
dithiolane groups
dithiolane-containing polymers
dithiolane-containing cyclic carbon...
Dithiolane Containing Amino

Supplementary materials

Felber (Thorn-Seshold) - Cyclic 5-membered disulfides are not selective substrates for TrxR - Supp v4.41
The supporting information contains details concerning experiments and analysis.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.