Table 1.
Steady-state kinetic parameters of AtPCOs 1–5 toward AtRAP2(2–15) at atmospheric O2
The turnover numbers (kcat), Michaelis constants (Km), and related maximum velocities (Vmax) of AtPCOs 1–5 for RAP2(2–15) were calculated by analyzing the initial rate of AtPCO-catalyzed cysteine oxidation (Fig. S3) as a subject of AtRAP2(2–15) concentration using the Michaelis–Menten model of enzyme kinetics (Fig. 4). Substrate inhibition was observed for AtPCOs 4 and 5 with inhibition constants calculated as 1.35 ± 0.24 and 3.78 ± 1.03 mm, respectively.
| AtPCO | kcat | Km | Vmax |
|---|---|---|---|
| s−1 | mm | μmol min−1 mg−1 | |
| 1 | 4.18 ± 0.09 | 0.24 ± 0.02 | 7.14 ± 0.16 |
| 2 | 1.98 ± 0.04 | 0.09 ± 0.01 | 3.45 ± 0.08 |
| 3 | 4.70 ± 0.17 | 0.56 ± 0.06 | 8.43 ± 0.31 |
| 4 | 31.0 ± 3.49 | 0.69 ± 0.11 | 63.4 ± 7.13 |
| 5 | 7.90 ± 0.74 | 0.16 ± 0.03 | 16.1 ± 1.51 |