Bacterial expression and kinetic characterization of the human monoamine-sulfating form of phenol sulfotransferase.

The cDNA for the human monoamine-sulfating form of phenol sulfotransferase (hM-PST) was isolated from a T47D human breast carcinoma lambda gt10 cDNA library, and the active enzyme was expressed in Escherichia coli. Expressed hM-PST was very similar to the brain, intestinal, and platelet forms of the enzyme in its physical, immunological, and kinetic properties. The ability of hM-PST to sulfate a number of xenobiotics was examined and compared with the bacterially expressed human phenol-sulfating form of PST (hP-PST). The translation product of the T47D hM-PST cDNA was 92% identical to that of liver hP-PST. Monoamine neurotransmittors, such as epinephrine and dopamine, were maximally conjugated at lower concentrations by expressed hM-PST (2 and 20 microM, respectively) than by hP-PST (1 and 1 mM, respectively). In contrast, simple phenols--such as p-nitrophenol, acetaminophen, and alpha-naphthol--were maximally conjugated at lower concentrations (4 microM, 20 microM, and 0.5 microM, respectively) by hP-PST than by hM-PST (1 mM, 1.5 mM, and 50 microM, respectively). Minoxidil was sulfated at similar rates and concentrations (7 mM) by both forms of PST. None of the estrogens or related compounds, such as beta-estradiol, 17 alpha-ethinylestradiol, diethylstilbestrol, equilenin, or genistein tested as substrates were sulfated by hM-PST; however, all of these compounds were substrates for hP-PST. As with hP-PST, the hydroxysteroids dehydroepiandrosterone and cortisol were not sulfated by hM-PST.(ABSTRACT TRUNCATED AT 250 WORDS)