TABLE 4.
Kinetic parameters determined for purified recombinant wild-type and variant citrate synthases with mutations matching those in strains EVT1 to EVT4a
| Citrate synthase |
Km (μM) |
Vmax
(μmol min−1 mg protein−1) |
Kcat (min−1) |
Kcat/Km (min−1
mM−1) |
|---|---|---|---|---|
| WT | 154 ± 25 | 4.8 ± 0.3 | 232 ± 14 | 1,506 ± 88 |
| R119L (EVT1) | 45 ± 12 | 5.6 ± 0.4 | 268 ± 18 | 5,955 ± 613 |
| A384T (EVT2) | 62 ± 6 | 4.0 ± 0.1 | 192 ± 7 | 3,096 ± 119 |
| G136S (EVT3) | 37 ± 4 | 4.5 ± 0.1 | 214 ± 7 | 5,783 ± 90 |
| A160V (EVT4) | 42 ± 7 | 4.2 ± 0.2 | 202 ± 10 | 4,809 ± 181 |
a
The data shown are means and standard deviations of at least three independent rate measurements over a range of oxaloacetate concentrations at a fixed concentration of acetyl-CoA, using the DTNB assay for CoA formation (see Materials and Methods).