Table I. Enzyme kinetic properties of recombinant AaTPS1 and AcTPS1.
Purified recombinant enzymes were obtained by Ni2+ affinity and gel filtration chromatography. Kinetic parameters were determined for GDP (1–50 µm) in the presence of 20 mm MgCl2 and for Mg2+ (0.2–25 mm) and Mn2+ (0–500 µm) in the presence of 25 µm GDP. All values represent the mean ± se, n = 3. kcat, Turnover; Vmax, maximum velocity.
| Enzyme | Km | Vmax | kcat | kcat/Km |
|---|---|---|---|---|
|
µm |
% |
s−1 |
s−1 mm−1 |
|
| AcTPS1 | ||||
| GDP (Mg2+) | 6.1 ± 0.2 | 0.0076 ± 0.0004 | 1.3 ± 0.08 | |
| Mg2+ (GDP) | 1478 ± 103 | 100 | ||
| Mn2+ (GDP) | 20.2 ± 2.0 | ∼200 | ||
| AaTPS1 | ||||
| GDP (Mg2+) | 13.1 ± 1.0 | 0.0195 ± 0.0020 | 1.5 ± 0.10 | |
| Mg2+ (GDP) | 1503 ± 208 | 100 | ||
| Mn2+ (GDP) | 28.6 ± 1.1 | ∼80 |