Figure 2
17β-estradiol (E2) sulfation by recombinant SULT1A1 allozymes. SULT1A1*2 has lower capacity to sulfate E2 than SULT1A1*1. One hundred nanograms of purified recombinant SULT1A1*1 and SULT1A1*2 allozymes were evaluated for capacity to sulfate E2 in a radiometric sulfotransferase assay. Assay conditions included 10 μM 3'-phosphoadenosine-5'-phosphosulfate (the sulfate donor) and increasing concentrations of E2 (0–250 μM). Data were evaluated on GraphPad Prism 3.0b (GraphPad Software Inc..) and fit to the Michaelis-Menten equation. SULT1A1*1, Km = 25.73 ± 7.28 μM, Vmax = 17.5 ± 1.71 pmol/min per mg protein; SULT1A1*2, Km = 24.74 ± 20.24 μM, Vmax = 3.55 ± 0.99 pmol/min per mg protein (Vmax, P < 0.0001).