Table 2.
Enzyme | KmdTTP (μM) | Kcat (s−1) | Kcat/Km (μM−1 S−1) | |
---|---|---|---|---|
poly(rA):oligo(dT)15 | WT | 14 | 2.4 | 0.18 |
Asp151→Glu | 690 | 2.1 × 10−5 | 0.3 × 10−7 | |
Asp213→Glu | 510 | 0.15 | 0.29 × 10−3 | |
Asp214→Asn | 34 | 0.02 | 0.59 × 10−3 | |
Asp214→Glu | 78 | 0.031 | 0.41 × 10−3 | |
Asp214→Gln | 26 | 0.0016 | 0.62 × 10−4 | |
Enzyme | KmdGTP (μM) | Kcat (s−1) | Kcat/Km (μM−1 S−1) | |
poly(rC):oligo(dG)18 | WT | 42 | 6.2 | 0.15 |
Asp151→Glu | ND | ND | ND | |
Asp213→Glu | 260 | 0.67 | 0.26 × 10−2 | |
Asp214→Asn | 42 | 0.12 | 0.28 × 10−2 | |
Asp214→Glu | 64 | 0.19 | 0.3 × 10−2 | |
Asp214→Gln | ND | ND | ND | |
poly(dC):oligo(dG)18 | ||||
WT | 19 | 24 | 1.3 | |
Asp151→Glu | ND | ND | ND | |
Asp213→Glu | 140 | 0.88 | 0.64 × 10−2 | |
Asp214→Asn | 4 | 0.044 | 0.012 | |
Asp214→Glu | 14 | 0.12 | 0.86 × 10−2 | |
Asp214→Gln | ND | ND | ND |
The steady-state parameters were derived using the template/primer indicated and corresponding dNTP substrate as described in Materials and Methods. ND, not determined.