Table 2. Effects of 5′-end modifications on the exo/endonuclease activities of the Hex1-N2 and hFen1 enzymes.
| 5′-End modification | Double-stranded | 5′-Flap | |||||
|---|---|---|---|---|---|---|---|
| Hex1-N2 | hFen1 | Hex1-N2 | hFen1 | ||||
| pmol min–1 mg–1 | RA | pmol min–1 mg–1 | pmol min–1 mg–1 | RA | pmol min–1 mg–1 | RA | |
| Hydroxyl (OH) | (1.0 ± 0.3) × 104 | 1 | n.d. | (1.0 ± 0.1) × 104 | 1 | (1.2 ± 0.1) × 105 | 1 |
| Phosphate | (1.3 ± 0.4) × 105 | 13 | n.d. | (0.6 ± 0.2) × 105 | 6 | (2.0 ± 0.4) × 105 | 1.7 |
| Biotin | (1.0 ± 0.3) × 103 | 0.1 | n.d. | (0.8 ± 0.2) × 103 | 0.1 | (1.4 ± 0.3) × 105 | 1.2 |
The averages and standard deviations of three independent experiments are shown, as well as relative activity (RA) compared to substrates containing a 5′-OH group. Substrates are as described in Table 1. See Materials and Methods for details. n.d., not determined.