Table 3.
Oxidative half-reaction of OYE-T37A vs. the wild-type enzyme
|
Kd, μM
|
kox, s−1
|
Ratio of kox (T37A/Wild type) | |||
|---|---|---|---|---|---|
| T37A | Wild type | T37A | Wild type | ||
| 2-Cyclohexenone* (CHX) (1) | 28 | 32 | 298 | 102 | 2.9 |
| 3-Methyl-2-CHX (2) | 50 | 64 | 0.17 | 0.062 | 2.7 |
| 1,2-Cyclohexanedione (3) | 570 | 520 | 100 | 32 | 3.1 |
| Cinnamaldehyde† (CNA) (4) | 105 | 125 | 77 | 17 | 4.5 |
| α-methyl-trans-CNA (5) | 11 | 8.6 | 256 | 34 | 7.5 |
| 3-Penten-2-one (6) | 590 | 430 | 50.9 | 15.6 | 3.3 |
| Mesityl oxide (7) | 250 | ≥1,000 | 0.261 | ∼0.03 | 9.0 |
| 3-Methyl-2-butenal (8) | 47 | 70 | 3.0 | 1.7 | 1.8 |
| Crotonaldehyde (M−1 s−1) (9) | — | — | 3.4 × 105 | 1.6 × 105 | 2.1 |
| Molecular oxygen* (M−1 s−1) | — | — | 1.0 × 105 | 3.8 × 103 | 26 |
| 1-Nitrocyclohexene† (M−1 s−1) (11) | — | — | 2.5 × 106 | 6.1 × 105 | 4.1 |
The Kd values and rate constants given were obtained by analysis of at least four duplicate reactions at each concentration of oxidant studied and which varied by less than 5%. The values given therefore have corresponding associated error limits.
*
Data for the wild-type enzyme are from ref. 11.
†
Data for the wild-type enzyme are from ref. 13.
Structure of the substrates as labeled in the table (the cis/trans composition of 3-penten-2-one is not known):
 |