TABLE 4.
Substrate | Vmax (U mg−1) | Km (mM) | kcatb (s−1) | kcat/Km (s−1 mM−1) |
---|---|---|---|---|
d-Glucose | 926 ± 9 | 6.2 ± 0.5 | 2,003 | 323.0 |
2-Deoxy-d-glucose | 38 ± 1 | 8.3 ± 0.7 | 83 | 10.0 |
d-Mannose | 186 ± 6 | 106 ± 8 | 401 | 3.8 |
d-Galactose | 73 ± 5 | 952 ± 9 | 159 | 0.2 |
d-Xylose | 33 ± 1 | 384 ± 27 | 72 | 0.2 |
Initial reaction velocities of GOX were determined for each sugar at 25°C under oxygen saturation in 0.1 M sodium acetate, pH 6.0. Data are the means (± standard deviations for Vmax and Km) of at least three independent measurements.
The kcat values were calculated per mole of native GOX, since only the dimeric form of the enzyme exhibits activity.