Table 1. Rate Constants (kcat) and Primary Kinetic Isotope Effects (Dkcat) of Double Mutant Soybean Lipoxygenase L546A/L754A at Varied Temperature.
| T (°C) | kcat-H (10–2 s–1)a | kcat-D (10–5 s–1)b | Dkcatc |
|---|---|---|---|
| 5 | 0.70 (0.075) | 1.11 (0.08) | 630 (68) |
| 10 | 0.85 (0.072) | 1.20 (0.14) | 708 (60) |
| 15 | 1.25 (0.11) | 1.65 (0.14) | 760 (67) |
| 20 | 1.30 (0.10) | 2.35 (0.14) | 553 (43) |
| 25 | 1.65 (0.12) | 2.65 (0.10) | 624 (46) |
| 30 | 2.25 (0.13) | 3.25 (0.04) | 692 (43) |
a
Determined by continuous UV–vis protocol. Each value is the average of duplicate measurements, and the error is the standard error of the average.
b
Determined by discontinuous HPLC protocol. Each value is the average of duplicate measurements except for that at 30 °C, which is the average of triplicate measurements; the error is the standard error of the average.
c
Dkcat = kcat-H/kcat-D. This error is calculated on the basis of an error propagation equation for the ratio of rate constants, as previously described.45