Table 1

Sulfation of substrates catalyzed by expressed human P-PST-1, M-PST, EST, ST1B2, and DHEA-ST. Assays were performed as described in the text using each substrate at its optimal concentration (noted in parentheses in table) for each ST. Reactions were run in triplicate and results are expressed as pmol sulfated product/min/mg protein and k_M values are also shown for the ropi metabolites. For comparison the k_M values of the human STs with other substrates are; P-PST-1 with 0.11 μM 4-nitrophenol (Lewis, 1997), M-PST with 1.3 μM dopamine (Hartman, 1998), EST with 5 nM β-estradiol (Zhang, 1998), ST1B2 with 5 μM 1-naphthol (Wang, 1998), and DHEA-ST with 1.6 μM DHEA (Falany and Roth, 1993).