Pemetrexed influx kinetics as a function of pH
Pemetrexed Km and Vmax values are based upon analysis of initial uptake rates in PCFT-transfected HepG2 cells. Data are the mean ± S.E.M. from three independent experiments. The Km values for MTX and folic acid were reported previously (Qiu et al., 2006) and are listed in the table for the purpose of comparison.
| pH | Pemetrexed INFLUX | Influx, Km | ||
|---|---|---|---|---|
| Km | Vmax | MTX | Folic Acid | |
| μM | pmol/mg protein/2 min | μM | ||
| 5.5 | 0.8 ± 0.1 | 227 ± 6 | 3.4 | 1.3 |
| 6.0 | 3.4 | 1.5 | ||
| 6.5 | 2.1 ± 0.2 | 174 ± 6 | 7.3 | 2.7 |
| 7.0 | 4.6 ± 0.9 | 175 ± 10 | 16.3 | 6.0 |
| 7.1 | 5.9 ± 0.9 | 165 ± 8 | ||
| 7.2 | 12.5 ± 0.8 | 161 ± 4 | ||
| 7.4 | 12.7 ± 1.2 | 141 ± 5 | 131 | 56.2 |