Table 4.
Kinetic parameters of N. europaea ADP-Glc PPase for ATP and UTP in presence of Pyra
| Nucleotide | Metal cofactor | Vmax (U/mg) | Km (mM) | kcat/Km (mM−1 · s−1) |
|---|---|---|---|---|
| ATP | Mg2+ | 73 ± 2 (1.5 ± 0.3) | 0.44 ± 0.03 (0.32 ± 0.03) | 550 ± 40 (4.6 ± 0.8) |
| Co2+ | 25 ± 1 (0.89 ± 0.04) | 0.10 ± 0.01 (1.1 ± 0.2) | 800 ± 70 (0.8 ± 0.1) | |
| UTP | Mg2+ | 1.4 ± 0.4 (3 ± 1) | 5 ± 2 (3 ± 1) | 1.0 ± 0.4 (1.2 ± 0.9) |
| Co2+ | 11.5 ± 0.5 (1.3 ± 0.3) | 1.3 ± 0.1 (2.4 ± 0.3) | 30 ± 3 (0.5 ± 0.1) |
a
The concentration of Mg2+ was 15 mM in both ATP and UTP assays, while that of Co2+ was 1 and 3 mM, respectively, when ATP and UTP were the substrates. The numbers in parentheses denote the ratio between the respective parameter determined in the presence and in the absence of 5 mM Pyr.