Table 1.
Enzyme activity of PRISEs from A. thaliana. The kinetic constants for the cosubstrate were determined using progesterone as the substrate.
| Enzyme (Substrate) | Km (µM) |
kcat (s−1) |
Catalytic Efficiency (s−1 M−1) |
|---|---|---|---|
| rAtStR2 | |||
| rAtStR2 (progesterone) | 64.7 | 0.15 | 2314 |
| rAtStR2 (MVK) | 157.5 | 0.03 | 163 |
| rAtStR2 (NADPH2) | 41.0 | 0.12 | 2927 |
| Other PRISEs of cluster II | |||
| rEcP5βR2 (progesterone) a | 82 | 0.05 | 552 |
| rEcP5βR2 (MVK) a | 224 | 0.05 | 245 |
| rCrP5βR6 (progesterone) a | 75.5 | 0.40 | 5530 |
| rCrP5βR6 (MVK) a | 118 | 0.03 | 261 |
| rAtStR1 and rAtSt5βR1_F153A_F342A | |||
| rAtStR1 (progesterone) b | 124.8 | 0.28 | 2244 |
| rAtStR1 (MVK) b | 75.5 | 0.20 | 7299 |
| rAtStR1_F153A_F342A (progesterone) c | 217 | 2.00 | 9218 |
| rAtStR1_F153A_F342A (MVK) c | - | n.a. | - |
| Other PRISEs of cluster I | |||
| rEcP5βR1 (progesterone) b | 77 | 0.01 | 31 |
| rEcP5βR1 (MVK) b | 344 | 0.72 | 2143 |
| rCrP5βR4 (progesterone) b | 153 | 0.02 | 123 |
| rCrP5βR4 (MVK) b | 123 | 0.20 | 1562 |
| Other MVK-converting enzymes | |||
| AtAER (MVK) d | 55.0 | 83.0 | 1,500,000 |
| AtAOR (MVK) e | 2880 | 74.0 | 25,700 |