Molecular cloning and characterization of rat ST1B1 and human ST1B2 cDNAs, encoding thyroid hormone sulfotransferases

Ken Ichi Fujita, Kiyoshi Nagata, Shogo Ozawa, Hironobu Sasano, Yasushi Yamazoe

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67 Citations (Scopus)


Human and rat cDNAs encoding thyroid hormone sulfotransferases have been isolated from their liver cDNA libraries. The isolated sulfotransferases, termed rat ST1B1 and human ST1B2, share 77 and 74% homologies at nucleotide and deduced amino acid levels. These forms showed less than 36 and 56% homologies to hydroxysteroid and aryl sulfotransferases, indicating that they constitute a new gene subfamily of aryl sulfotransferase. Expression of ST1B1 and ST1B2 in COS-1 cells resulted in the appearance of 33.0 and 32.5 kDa proteins, respectively, whose mobilities were identical with proteins detected in rat and human livers in Western blots using antibodies raised against ST1B1 and ST1B2 produced in Escherichia coli. The recombinant forms catalyzed sulfation of p-nitrophenol, 3,3',5-triiodothyronine (T3) and dopamine, but not of β-estradiol and dehydroepiandrosterone, ST1B1 and ST1B2 showed higher affinities for formation of T3 sulfate (apparent K(m) 40.2 and 63.5 μM, respectively) than did thermostable phenol sulfotransferase ST1A3 (apparent K(m) 413 μM) or thermolabile phenol sulfotransferase ST1A5 (apparent K(m) 180 uM). These data indicate that the newly characterized sulfotransferases constitute a distinct ST1 subfamily of enzymes catalyzing the sulfation of T3 as a typical endogenous substrate in rats and humans.

Original languageEnglish
Pages (from-to)1052-1061
Number of pages10
JournalJournal of biochemistry
Issue number5
Publication statusPublished - 1997 Nov


  • Aryl sulfotransferase
  • Molecular cloning
  • New gene subfamily
  • Recombinant form
  • Thyroid hormone

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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