Table 1.
Affinities of nutrient sensors for their amino acid substrates and corresponding plasma concentrations of those amino acids (Data from Stegink et al., 1991; Stein and Moore, 1954; Piyankarage et al., 2008)
| AA | AA binding protein | Kd (μM) | Plasma Concentration (μM) | Interstitial Concentration | Free Cytosolic Concentration | |||
|---|---|---|---|---|---|---|---|---|
| Fed | Fasted | Fed | Fasted | Fed | Fasted | |||
| Leu | Sestrin1 | 10–15 | 287 | 129 | ? | ? | ? | ? |
| Sestrin2 | 20 | 287 | 129 | ? | ? | ? | ? | |
| Sestrin3 | N/A | 287 | 129 | ? | ? | ? | ? | |
| LRS | 45 | 287 | 129 | ? | ? | ? | ? | |
| dSestrin | 100 | ? (mm range for other AAs) | ? | ? | ? | ? | ||
| Arg | CASTOR1 | 30 | 161 | 97 | ? | ? | ? | ? |
| CASTOR2 | N/A | 161 | 97 | ? | ? | ? | ? | |