TABLE 2

Kinetic parameters for the transport of E-sul and EG by HEK293 cells expressing each single TM-substituted OATP1B1 protein

Data shown in Fig. 7 were used to determine these parameters calculated by nonlinear regression analysis as described under Materials and Methods. Each parameter represents the mean ± computer-calculated S.D.


Transporter

Km

Corrected Vmax

Corrected Vmax/Km
μM pmol/min/mg protein μl/min/mg protein
E-sul
    OATP1B1 0.246 ± 0.038 43.8 ± 3.3 178 ± 18
    1B1-TM7 0.120 ± 0.044* 33.2 ± 5.0 278 ± 75
    1B1-TM8 4.35 ± 0.66** 87.1 ± 10.7** 20.0 ± 1.0**
    1B1-TM9 1.82 ± 0.37** 119 ± 17** 65.3 ± 5.9**
EG
    OATP1B1 6.31 ± 0.44 88.6 ± 4.6 14.0 ± 0.4
    1B1-TM7 5.02 ± 1.07 78.1 ± 9.8 15.6 ± 2.0
    1B1-TM8 Not significantly transported
    1B1-TM9
8.11 ± 1.60
104 ± 16
12.9 ± 1.1
  • * P < 0.05, significantly different from native OATP1B1.

  • ** P < 0.01, significantly different from native OATP1B1.