Chapter 7: Cysteine to Taurine: Thiol to Sulfonic Acid
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Published:10 Jun 2020
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Special Collection: 2020 ebook collectionSeries: Chemical Biology
The Chemical Biology of Sulfur, The Royal Society of Chemistry, 2020, ch. 7, pp. 161-175.
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One of the strategies for controlling cellular levels of the free amino acid cysteine and its nucleophilic, potentially toxic thiolate anion is enzymatic oxygenation. The three possible S-oxidation states are monooxygenated sulfenate, dioxygenated sulfinate and trioxygenated sulfonate. The end point metabolite from S-oxygenation is the decarboxylated sulfonate taurine. The three oxygens are introduced by two enzymes, the first using both oxygen atoms from a molecule of O2, the third being obtained from water. Taurine accumulates as an osmolyte in some tissues and is a conjugation moiety in gastrointestinal retrieval of bile acids such as taurocholic acid.