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Updated: Jul 18, 2026

Synthesis and Assay of Vibrio Quorum Sensing Inhibitors
Published on: May 31, 2024
Reversible covalent inhibition of a phenol sulfotransferase by coenzyme A
Sundari Chodavarapu1, Heather Hertema, Tien Huynh
1Department of Biochemistry, Alma College, Alma, MI 48801, USA.
Abstract:
Phenol sulfotransferases (SULTs), which normally bind 3'-phosphoadenosine-5'-phosphosulfate as the donor substrate, are inhibited by CoA and its thioesters. Here, we report that inhibition of bovine SULT1A1 by CoA is time-dependent at neutral pH under non-reducing conditions. The rates of inactivation by CoA indicate an initial reversible SULT:CoA complex with a dissociation constant of 5.7 microM and an inactivation rate constant of 0.07 min(-1). Titrations with CoA and prolonged incubations reveal that inactivation of the dimeric enzyme is stoichiometric, consistent with the observation of complete conversion of the protein to a slightly decreased electrophoretic mobility. Both activity and normal electrophoretic migration are restored by 2-mercaptoethanol. Mutagenesis demonstrated that Cys168 is the site of CoA adduction, and a consistent model was constructed that reveals a new SULT molecular dynamic. Cysteine reaction kinetics with Ellman's reagent revealed a PAPS-induced structural change consistent with the model that accounts for binding of CoA.
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