TABLE 2.
Kinetic parameters of archaeal RNases HIIa
| Enzyme | Km (μM) | kcat (min−1) | kcat/Km |
|---|---|---|---|
| PabRNase HII | 0.50 ± 0.15 | 5.57 ± 0.54 | 11.14 |
| AfuRNase HII | 0.06 ± 0.15 | 8.0 ± 0.23 | 133.3 |
a
Hydrolyses of RNA-DNA/DNA substrates (S1) were carried out at 60°C in PabRNase HII reaction buffer as described in Materials and Methods. The data were fitted by nonlinear regression using the Marquardt-Levenberg algorithm (EnzFitter 2.0; BioSoft) to the Michaelis-Menten equation. The Km and Vmax values obtained from the fit were used to calculate the catalytic efficiency (kcat/Km) of PabRNase HII. The kinetic values shown are the averages of at least triplicate determinations and are shown with standard deviations. The values for AfuRNase HII are from a previous study (4).