TABLE 3.
Effect of H932Y/A mutations on discrimination against mismatches
Kinetic parameters governing misincorporation opposite a template T catalyzed by H932Y and H932A are summarized as derived from the data shown in Figs. 3 and 5. The S.E. estimates (±) were derived by error propagation from the values shown in Table 2.
| Enzyme/nucleotide | kcat | Km | kcat/Km | Discrimination |
|---|---|---|---|---|
| s−1 | μm | μm−1 s−1 | ||
| WT | ||||
| TTP | 0.01 ± 0.004 | 81.8 ± 10.9 | 0.0001 ± 0.00005 | 430,000 |
| dCTP | 0.06 ± 0.018 | 1030 ± 193 | 0.00006 ± 0.00002 | 717,000 |
| dGTP | 6.6 ± 7.4 | 1300 ± 1600 | 0.005 ± 0.008 | 8,600 |
| H932Y | ||||
| TTP | 0.0004 ± 0.0005 | 154 ± 60 | 0.000002 ± 0.000003 | 150,000 |
| dCTP | 0.0003 ± 0.002 | 750 ± 3875 | 0.0000004 ± 0.000003 | 750,000 |
| dGTP | 1.2 ± 0.4 | 24000 ± 9600 | 0.00005 ± 0.00003 | 6,000 |
| H932A | ||||
| TTP | 0.0003 ± 0.0004 | 260 ± 150 | 0.000001 ± 0.000002 | 600,000 |
| dCTP | 0.0005 ± 0.001 | 1450 ± 1330 | 0.0000003 ± 0.0000007 | 2,000,000 |
| dGTP | 0.27 ± 0.06 | 5150 ± 1500 | 0.00005 ± 0.00002 | 12,000 |