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Title of article :
Reversible covalent inhibition of a phenol sulfotransferase by coenzyme A
Author/Authors :
Chodavarapu، نويسنده , , Sundari and Hertema، نويسنده , , Heather and Huynh، نويسنده , , Tien and Odette، نويسنده , , Jessica R. Miller، نويسنده , , Rachel and Fullerton، نويسنده , , Aaron and Alkirwi، نويسنده , , Jason and Hartsfield، نويسنده , , D’Juan and Padmanabhan، نويسنده , , Kaillathe and Woods، نويسنده , , Caleb and Beckmann، نويسنده , , Joe D.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Pages :
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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 μM 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.
Keywords :
Kinetics , CoA , REGULATION , induced fit , Model , sulfotransferase , SULT1A1 , Inactivation , Inhibition
Journal title :
Archives of Biochemistry and Biophysics
Journal title :
Archives of Biochemistry and Biophysics
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Link To Document :