Table 1. Kinetic parameters of pyrophosphorolysis reaction. Susceptibility of TEC U10 to PPi was determined in the absence and in the presence of Nun. TECs U9 and U10 were incubated with [PPi] varying from 10 μM to 2.5 mM. For the TEC U10, the experiment was also performed in the presence of 1 μM Nun. The pyrophosphorolysis rate constants were obtained by single exponential fits of the averaged data points, plotted versus [PPi], and the Km and Vmax values were obtained by fitting the data to a Michaelis–Menten equation.
| TEC | Km, mM | V max, min−1 |
|---|---|---|
| U9 | 0.39 ± 0.09 | 0.5 ± 0.03 |
| U10 | 0.32 ± 0.14 | 15.7 ± 1.9 |
| U10 + Nun | 0.24 ± 0.02 | 160 ± 3 |