It seems that most thioesters are highly reactive in cells and blood due to the high concentration of biological thiols. Are there any derivatives of thioesters that are stabilized at physiological conditions by certain functional groups? Fatty acid metabolism is mediated by transfer of CoA to the fatty acid, so I imagine this bond must be somewhat stable. Is this stabilized by the nitrogen that sits a couple carbons away from the thioester?

  • $\begingroup$ I think the most important thing is simply pH. $\endgroup$
    – Mithoron
    Jan 15, 2023 at 19:04
  • $\begingroup$ Stability between pH 4 and 7 (physiologically relevant conditions) is pretty much unchanged for all thioesters. I was thinking transthioesterification would have a greater effect on bond stability than pH. $\endgroup$
    – toodles
    Jan 16, 2023 at 3:32
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    $\begingroup$ can you give a source for your claim that "most thioesters are highly reactive in cells and blood"? Biological thioesters that I'm familiar with are generally quite stable and only undergo transthioesterification at a high rate in the presence of enzymes that catalyze those reactions. $\endgroup$
    – Andrew
    Jan 16, 2023 at 17:44
  • $\begingroup$ And my point is that at this pH their resistance to hydrolysis is good enough. $\endgroup$
    – Mithoron
    Jan 17, 2023 at 0:30
  • $\begingroup$ Sure, I understood your point, i was just explaining that my concern is not hydrolysis, its transthioesterification. There are countless reports showing extremely short half lives for thioesters in the presence of other thiols like N-Acetylcysteine and glutathione, which are present in high concentrations in cells and blood. The paper below shows S-methylthioacetate has a half life of 38 h in the presence of 1 mM of 2- sulfonatoethanethiolate. Physiological glutathione conc is 5-10mM resulting in thioester half life of 1hr link.springer.com/article/10.1007/s11084-011-9243-4 $\endgroup$
    – toodles
    Jan 18, 2023 at 1:30


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