HUMAN LIVER TRIIODOTHYRONINE SULFOTRANSFERASE - COPURIFICATION WITH PHENOL SULFOTRANSFERASES

To ascertain whether triiodothyronine (T-3) sulfotransferase coeluted with the known phenol sulfotransferases (PSTs) during purification, human liver thermostable PST, thermolabile PST, and T-3 sulfotransferase were assayed with g-nitrophenol, dopamine, and T-3, respectively, Thermostable PST eluted from an ion-exchange column in two sequential peaks of activity (Peaks I and II), followed by a peak of thermolabile PST activity, There were three peaks of T-3 sulfotransferase with thermostable PST: two within thermostable PST Peak I, and one peak of T-3 Sulfotransferase activity within thermostable PST Peak II, There was a minor peak of T-3 sulfotransferase with thermolabile PST, Further purification of thermostable Peak I showed coelution of T-3 sulfotransferase with thermostable PST during gel filtration and affinity chromatography, SDS-PAGE revealed a major protein band at 31 kDa, Dehydroepiandrosterone sulfotransferase comprised only 4% of the final activity, This report demonstrates coelution of T-3 sulfotransferase with thermostable PST, shows a potential additional isozyme of T-3 sulfotransferase, and points out the apparent minimal role of dehydroepiandrosterone sulfotransferase in T-3 sulfation, The findings support the hypothesis that thermostable PST is the predominant human liver T-3 sulfotransferase activity.