Comparison of adenosine transport kinetics with organic cation substrates
Values are given as means ± S.D. (n = 3). All values were determined in the same MDCK cell line stably expressing human PMAT. For organic cations, kinetic data were taken from Engel and Wang (2005).
| Substrate | Km | Vmax | Vmax/Km |
|---|---|---|---|
| μM | pmol/(min · mg) protein | μl/(min · mg) protein | |
| MPP+ | 33 ± 7 | 2800 ± 116 | 85 |
| Serotonin | 114 ± 12 | 6524 ± 197 | 57 |
| Dopamine | 329 ± 8 | 18,222 ± 168 | 55 |
| Tyramine | 283 ± 23 | 5055 ± 147 | 18 |
| Histamine | 10,471 ± 2250 | 99,610 ± 17,299 | 9.5 |
| Norepinephrine | 2606 ± 258 | 20,561 ± 902 | 7.9 |
| Adenosine | 413 ± 107 | 2013 ± 140 | 4.9 |
| Epinephrine | 15,323 ± 3947 | 38,442 ± 7705 | 2.5 |
| Tetraethylammonium | 6593 ± 1702 | 5827 ± 918 | 0.9 |