TABLE 3.
Kinetic constants generated for wild type and G533A muCOX-2 using ω-6 and ω-3 fatty acid substrates
Values were derived from three independent determinations (±S.E.). utilizing an oxygen electrode. Vmax and subsequent kcat values are corrected for the percentage of mono- and bisoxygenated products. Efficiency (E) is defined as the kcat/ Km. ND, not determined.
| Construct | LA (18:2 ω-6) |
αLA (18:3 ω-3) |
SA (18:4 ω-3) |
EPAa (20:5 ω-3) |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| kcat | Km | E | kcat | Km | E | kcat | Km | E | kcat | Km | E | |
| s−1 | μm | s−1 | μm | s−1 | μm | s−1 | μm | |||||
| Wild type | 10.8 ± 0.3 | 18.3 ± 1.5 | 0.6 | 14.3 ± 0.3 | 38.4 ± 2.2 | 0.4 | 8.8 ± 0.2 | 14.9 ± 1.3 | 0.6 | 8.7 ± 0.2 | 9.5 ± 0.7 | 0.9 |
| G533A | ND | ND | ND | 11.8 ± 0.5 | 27.8 ± 3.7 | 0.4 | 9.9 + 0.2 | 10.5 ± 0.7 | 0.9 | 4.2 ± 0.1 | 13.6 ± 1.5 | 0.3 |
a Values for wild type enzyme are from Ref. 15.