Analysis of transport kinetics for the D. melanogaster and human catecholamine transporters
| dDAT | hDAT | hNET | |||||||
|---|---|---|---|---|---|---|---|---|---|
| KT | Vmax | Vmax/KT | KT | Vmax | Vmax/KT | KT | Vmax | Vmax/KT | |
| μM | μM | μM | |||||||
| DA | 4.8 ± 0.4 | 1.4 | 16 | 3.7 ± 1.1 | 1.2 | 9.1 | 0.7 ± 0.2 | 0.8 | 2.6 |
| NE | 55 ± 9 | 1 | 1 | 28 ± 7 | 1 | 1 | 2.3 ± 0.3 | 1 | 1 |
| TA | 61 ± 3 | 0.6 | 0.5 | 6.5 ± 0.9 | 0.4 | 1.7 | 0.3 ± 0.1 | 0.3 | 2.3 |
| Epi | 471-a | 0.4 | 0.5 | ||||||
Uptake of [3H]amine was determined in stable transfected MDCK cells (dDAT-MDCK, hNET-MDCK, and GFPhDAT-MDCK) as described underExperimental Procedures. K T values are presented as means ± S.E.M. from three to five experiments.V max values for different substrates for a given transporter were determined in parallel assays to compensate for differences in cell densities. V max values and the ratio V max/K T were normalized for NE = 1.
↵1-a Mean of n = 2 experiments.