TABLE 2.
StyA1 oxygenase activity in dependence of different FAD reductases
| FAD reductase | Molar amt (pmol) | FAD-reducing activity (mU)a | StyA1 oxygenase (molar amt [pmol]) | Epoxidation activity (mU)a | Relative activity (%)b | Efficiency of oxygenation |
|
|---|---|---|---|---|---|---|---|
| Styrene oxide per FADH2c | Relative efficiency (%)b | ||||||
| StyA2B | 62.5 | 13.2 | 125 | 0.58 (0.66) | 46 | 0.044 | 90 |
| 125 | 26.4 | 1.28 (1.43) | 100 | 0.049 | 100 | ||
| 250 | 52.8 | 1.22 (1.52) | 96 | 0.023 | 47 | ||
| StyB | 62.5 | 67.2 | 125 | 2.06 | 161 | 0.031 | 63 |
| 125 | 135.5 | 2.03 | 159 | 0.015 | 31 | ||
| 250 | 271 | 1.11 | 87 | 0.004 | 8 | ||
| PheA2 | 250 | 87 | 250d | 0.18 | 7 | 0.002 | 4 |
a
All experiments were performed in triplicate, and for oxygenations, a standard error of <20% was observed. Values in parentheses refer to experimentally obtained data comprising additional epoxidation activity of bifunctional StyA2B (0.019 U mg−1).
b
Normalized values set to 100% for equimolar StyA1/StyA2B reaction (for 125 pmol StyA1).
c
Efficiency is defined as the ratio of oxygenase-generated epoxide per reductase-generated FADH2.
d
With PheA2 as reductase, only higher amounts of StyA1 yielded reliable epoxidation rates.