Table 2.
Competitive inhibition by various substrates of [14C]aspartate uptake into proteoliposomes reconstituted with AtUCP1 or AtUCP2
The inhibition constants (Ki) were calculated from Dixon plots of the inverse rate of [14C]aspartate transport versus the competing substrate concentration. The competing substrates at appropriate concentrations were added together with labeled asparate to proteoliposomes containing 10 mm aspartate. The values are means ± S.E. of at least three independent experiments carried out in duplicate.
| Inhibitor |
Ki |
|
|---|---|---|
| AtUCP1 | AtUCP2 | |
| mm | ||
| α-Ketoglutarate | 3.3 ± 0.2 | 2.6 ± 0.2 |
| Cysteate | 2.2 ± 0.3 | 2.4 ± 0.2 |
| Cysteinesulfinate | 2.7 ± 0.3 | 2.3 ± 0.2 |
| Glutamate | 2.2 ± 0.2 | 2.3 ± 0.2 |
| Malate | 1.7 ± 0.2 | 2.2 ± 0.2 |
| Oxaloacetate | 2.6 ± 0.3 | 3.2 ± 0.2 |
| Sulfate | 3.6 ± 0.3 | 3.3 ± 0.3 |