TABLE 3.
Initial rates of serine receptor methylation
| Sample no. | Coexpressed receptors | Liganda |
Methylation (pmol/min) |
Background subtracted (pmol/min)b |
|||
|---|---|---|---|---|---|---|---|
| Serine | Aspartate | Rate ± SD | Ligand effectc | Rate ± SD | Ligand effectc | ||
| 1 | trTsrQQEQ/TarQQQQ | − | − | 0.34 ± 0.03 | 0.03 ± 0.04 | ||
| 2 | trTsrQQEQ/TarQQQQ | + | − | 0.68 ± 0.05 | 2.0 | 0.37 ± 0.06 | 12 |
| 3 | trTsrQQEQ/TarQQQQ | − | + | 0.36 ± 0.05 | 1.1 | 0.05 ± 0.05 | 1.6 |
| 4 | trTsrQQEQ/TarQQQQ | + | + | 0.65 ± 0.04 | 1.9 | 0.33 ± 0.04 | 11 |
| 5 | trTsrQQEQ/trTarQQQQ | − | − | 0.028 | |||
| 6 | trTsrQQEQ/trTarQQQQ | + | − | 0.042 | 1.5 | ||
| 7 | trTsrQQEQ/trTarQQQQ | − | + | 0.020 | 0.7 | ||
| 8 | trTsrQQEQ/trTarQQQQ | + | + | 0.050 | 1.8 | ||
| 9 | trTsrQEQE/TarQQQQ | − | − | 2.64 ± 0.24 | 2.34 ± 0.24 | ||
| 10 | trTsrQEQE/trTarQQQQ | + | − | 3.18 ± 0.42 | 1.2 | 2.88 ± 0.42 | 1.2 |
| 11 | trTsrQEQE/trTarQQQQ | − | + | 3.12 ± 0.18 | 1.2 | 2.82 ± 0.18 | 1.2 |
| 12 | trTsrQEQE/trTarQQQQ | + | + | 3.12 ± 0.06 | 1.2 | 2.82 ± 0.12 | 1.2 |
a
+ and − indicate the presence and absence, respectively, of serine (1 mM) or aspartate (1 mM).
b
The rate of methyl group incorporation (0.31 ± 0.02 pmol/min) into samples of coexpressed trTsrQQQQ and TarQQQQ was subtracted.
c
Rate in the presence of serine, aspartate, or both divided by the rate in the absence of ligand.