Table 1.
TCA kinetic constants for C270A, WT, TM3 and TM7 cysteine mutantsa. Bile acid affinity (Km) for all mutant constructs significantly different from controls, p < 0.05. Asterisks omitted for visual clarity.
| Construct | Taurocholate kinetics |
|
|---|---|---|
| Kt (μM) | Jmax (pmol/min/mg prot) | |
| C270A | 7.9 ± 1.95 | 655.6 ± 32.46 |
| WT | 11.6 ± 2.39 | 176.3 ± 7.08 |
| S128C | 17.24 ± 4.74 | 309.9 ± 20.7 |
| L145C | 16.51 ±3.77 | 281.2 ± 15.47 |
| L146C | 15.56 ± 3.52 | 1223 ± 65.60 |
| I147C | 22.72 ± 4.93 | 1454 ± 82.81 |
| F287C | 61.52 ± 5.86 | 1016 ± 32.77 |
| F289C | 34.44 ± 7.37 | 302.3 ± 18.49 |
| L291C | 35.44 ± 6.32 | 1047 ± 53.77 |
| Y293C | 72.03 ± 20.83 | 1364 ± 72.00 |
COS-1 cells transiently transfected as described in “Materials and Methods”. Uptake measured at TCA concentrations ranging from 0–150 μM (measured in triplicate). Kinetic data analyzed using Graphpad Prism software with constants determined via nonlinear least-square fitting procedures.