Table 3. Kinetic Properties of WT and Two Stabilized Variants.
| (S)-1-PEA |
pyruvate |
|||||
|---|---|---|---|---|---|---|
| enzyme | Tmapp (°C) | kcat (s–1) | KM (mM)a | kcat/KM (mM–1 s–1) | KM (mM) | kcat/KM (mM–1 s–1) |
| WT | 62 | 12.7 ± 0.1 | 9.6 ± 1.2 | 1.4 ± 0.1 | 4.4 ± 0.5 | 3.0 ± 0.3 |
| R4 | 80 | 56.7 ± 1.0 | 13.1 ± 1.6 | 4.4 ± 0.6 | 10.6 ± 1.6 | 5.5 ± 0.9 |
| R6 | 85 | 58.2 ± 0.8 | 11.5 ± 1.7 | 5.2 ± 0.8 | 13.5 ± 1.8 | 4.4 ± 0.6 |
a
Initial rates were determined by measuring acetophenone formation with varying concentrations (0–32 mM) of (S)-1-PEA as the amino donor and 50 mM pyruvate as the amino acceptor or with 50 mM (S)-1-PEA as the mino donor and varying concentrations (0–32 mM) of pyruvate as the amino acceptor.