KM (μm) | Vmax (pmol/min/mg) | Surface expression (% of wild type) | |
---|---|---|---|
WT | 0.24 ± 0.04 | 6.55 ± 0.23 | 100 ± 5 |
WT + 8-Br-cGMP | 0.20 ± 0.03 | 8.28 ± 0.13* | ND |
I425V | 0.26 ± 0.02 | 8.16 ± 0.59* | 104 ± 1 |
T276A | 0.19 ± 0.01 | 5.54 ± 0.11 | 104 ± 4 |
T276A-I425V | 0.12 ± 0.01* | 4.03 ± 0.26* | 103 ± 3 |
T276D | 0.11 ± 0.01* | 4.03 ± 0.11* | 95 ± 7 |
T276D-I425V | 0.08 ± 0.01* | 4.24 ± 0.21* | 95 ± 6 |
T276E | 0.13 ± 0.02* | 4.48 ± 0.19* | 87 ± 8 |
WT and hSERT mutants were tested to measure transport rate over a range (0.02–5 μm) of 5-HT concentrations. KM and Vmax were calculated by fitting the rate versus concentration data using Origin software (OriginLab). The results are from multiple experiments. Asterisks indicate KM and Vmax values significantly different (p < 0.05) from that of wild type. ND, Not determined.