The saturable uptake of [¹⁴C]E3040 conjugates in the presence and absence of inhibitors (fig. 8) was simultaneously fitted to equations 2 and 4 to determine the kinetic parameters. The uptake of [¹⁴C]E3040 glucuronide was described by one saturable (K _m = 73.3 ± 15.3 μM;V _max = 2.51 ± 0.49 nmol/min/10⁶ cells) and one nonsaturable (P _dif = 4.41 ± 0.74 μl/min/10⁶ cells) components. The uptake of [¹⁴C]E3040 sulfate was described by one saturable (K _m = 28.5 ± 2.7 μM; V _max= 8.96 ± 0.66 nmol/min/10⁶ cells) and one nonsaturable (P _dif = 5.51 ± 1.75 μl/min/10⁶cells) components. These K _m, V _maxand P _dif values for E3040 conjugates were not significantly different from those reported in table 4.