TABLE 1.
Kinetic characteristics of TMP and dThd analog monophosphates as substrates for recombinant TMPKa
| dThd analog | Km (μM) | Vmax (μmol/min/mg) | Kcat (s−1) | Relative efficiencyb (%) 1 |
|---|---|---|---|---|
| TMP | 12.3 ± 2.2 | 6 ± 0.9 | 2.4 ± 0.36 | 100 |
| l-FMAUMP | 21.7 ± 2.9 | 0.12 ± 0.02 | 0.05 ± 0.008 | 1.17 |
| d-FMAUMP | 7.0 ± 0.2 | 2.6 ± 1.7 | 1 ± 0.07 | 73 |
| d4TMP | 28.0 ± 1.7 | 0.23 ± 0.03 | 0.09 ± 0.01 | 1.6 |
a
The Km and Kcat values of the dThd analog monophosphates were evaluated by using 4.5 mM ATP as the phosphate donor. The reactions were carried out with 0.01 U of TMPK. Values are means ± standard deviations from three independent experiments.
b
A 100% relative efficiency of TMP corresponds to the rate of Kcat/Km.