Table I.
Kinetic constants of Spm, Nor-Spm, and N1-acetyl-Spm oxidation by recombinant AtPA01 expressed in E. coli
| Substrate | kcata | Kma | kcat/Km |
|---|---|---|---|
| s−1 | mm | s−1 mm−1 | |
| Spm | 2.7 ± 0.3 | 0.11 ± 0.02 | 24.1 |
| Nor-Spm | 6.9 ± 1.3 | 0.09 ± 0.01 | 81.4 |
| N1-acetyl-Spm | 0.2 ± 0.4 | 0.47 ± 0.02 | 0.5 |
a
Enzymatic activity of recombinant AtPAO1 has been determined in 100 mm Tris-HCl, pH 8.0, using a constant O2 concentration at the air-saturated level and an amine substrate concentration either saturating (for apparent kcat determination) or varying between 50 and 400 μm for Spm and N1-acetyl-Spm and between 10 and 100 μm for Nor-Spm (for apparent Km determination). Data are mean ± se of at least three independent experiments.