Figure 4. Enzyme kinetics of UGT1A10-catalyzed glucuronidation of 17α-estradiol (A), 17β-estradiol (B), entacapone (C), and 4-MU (D) in the absence and presence of BSA.

The reactions with 17α-estradiol and 17β-estradiol were analyzed for the formation of 17α-estradiol-3-β-D-glucuronide and 17β-estradiol-3-β-D-glucuronide, respectively. The glucuronidation rates are presented as the average value ± S.E., and are expression level-normalized values. The concentrations of substrates were corrected for binding to 0.1% BSA. The determined enzyme kinetic parameters are presented in Table 2. See Materials and Methods for all further details.