Table 3.
Dissociation constants derived from microcalorimetric binding studies of different amines to sensor domains of the 10 receptors analyzed
| Protein | KD (uM) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Quaternary amines | Methyl-/ethyl-/ethanol amines* | Polyamine | |||||||
| Acetylcholine | Choline | TMAO | Methylamine | Ethylamine | Dimethylamine | Trimethylamine | Ethanolamine | Ethylenediamine | |
| R1† | 1,845 ± 1,120 | Nb‡ | Nb | 35.1 ± 3 | 19.6 ± 2 | 0.53 ± 0.02 | 10.0 ± 0.4 | Nb | Nb |
| R2 | Protein insoluble | ||||||||
| R3§ | Nb | Nb | Nb | Nb | Nb | Nb | Nb | 2.3 ± 0.1 | 29.6 ± 3 |
| R4¶ | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb |
| R5† | 581 ± 129 | 3.6 ± 0.1 | 1,742 ± 88 | Nb | Nb | 311 ± 79 | 1.2 ± 0.1 | Nb | Nb |
| R6† | Nb | Nb | Nb | Nb | Nb | Nb | 151 ± 4 | Nb | Nb |
| R7§ | Nb | 2,950 ± 217 | Nb | 16.6 ± 2 | Nb | 5.3 ± 0.4 | 12.6 ± 1 | 1.7 ± 0.02 | 12.3 ± 1 |
| R8† | 735 ± 24 | 183 ± 4 | Nb | 25.1 ± 3 | 46.1 ± 7 | 5.8 ± 1 | 24.0 ± 4 | Nb | Nb |
| R9§ | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb |
| R10§ | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb | Nb |
| PacA-LBD | Nb# | 113 ± 16# | Nd|| | Nb | Nb | Nb | 113 ± 6 | Nb | Nb |
*Volatile organic compound.
†No binding by ITC of L-carnitine, betaine, proline, and trigonelline.
‡No binding by ITC and/or thermal shift assay (increases above 2 ºC were considered significant).
§No binding by ITC of L-carnitine and trigonelline.
¶No binding by ITC of L-carnitine, betaine, and trigonelline.
#Reported previously in ref. 17.
||Not determined.
Dissociation constants below 10 µM are shown in bold face.