Table 2.
Kinetic parameters for transport of substrates by wild-type MRP2 and four SNP variants
| Substrates | Kinetic parameters |
WT | S789F | A1450T | V417I | T1477M |
|---|---|---|---|---|---|---|
| LTC4 | Km | 4 (1.8 – 6.5) |
3 (1.8 – 4.4) |
3 (2 – 3.6) |
9 (7.8 – 12.7)* |
6 (3.5 – 9) |
| Vmax | 1464 (1314–1713) |
732 (648 – 816)* |
658 (618–699)* |
1366 (1200–1531) |
1659 (1373–1945) |
|
| E23G | Km | 103 (73 – 133) |
235 (173 – 296)* |
106 (64 – 148) |
212 (95 – 330) |
172 (88 – 230) |
| Vmax | 1458 (1339–1578) |
615 (558–671)* |
855 (746–964)* |
1794 (1454–2134) |
1157 (975–1338)* |
|
| E217βG | Km | 84 (64–104) |
72 (67–76) |
88 (75–100) |
263 (241–285)* |
94 (89–100) |
| Vmax | 3154 (2691–3617) |
1799 (1732–1866)* |
2665 (2422–2907) |
2647 (2520–2773) |
2646 (2555–2737) |
|
| HC | 2.2 (1.4 – 3) |
2.4 (2.1 – 2.6) |
2 (1.6 – 2.4) |
1.1 (1.1 – 1.2)* |
1.8 (1.7–1.9) |
|
| TUDC | Km | 71 (65–78) |
64 (71–96) |
71 (57–86) |
74 (70–79) |
109 (103–116)* |
| Vmax | 595 (563–627) |
359 (343–376)* |
424 (376–472)* |
577 (553–600) |
671 (645–699)* |
|
| HC | 2 (1.7–2.3) |
2.3 (1.9–2.6) |
1.8 (1.3–2.3) |
2.6 (2.3–2.8) |
2.2 (2–2.4) |
The kinetic parameters [Km (µM); Vmax (pmol·mg−1·min−1); Hill coefficient (HC)] of ATP-dependent transport of leukotriene C4 (LTC4), estradiol-3 glucuronide (E23G), estradiol-17-glucuronide (E217G) and tauroursodeoxycholic acid (TUDC) were determined in Sf9 plasma membrane vesicles. Values in brackets are the 95% Confidence Limits. The values were calculated from the data shown in Figure 2.
*
Significantly different from WT, as determined by non- overlapping 95% Confidence Limits.