Table 1.
Apparent kinetic parameters of in vitro aminoacylation of WT and mutant hmtRNALeu(CUN) transcripts by human mitochondrial leucyl-tRNA synthetase
| hmtRNALeu(CUN) transcripts | kcat(10−3 s−1) | KM(μM) | kcat/KM(10−3 s−1 μM−1) | Relative kcat/KM |
|---|---|---|---|---|
| Wild type | 52.4 ± 1.8 | 23.9 ± 3.9 | 2.19 | 1 |
| U48C | 112.3 ± 1.0 | 39.1 ± 5.7 | 2.87 | 1.31 |
| U48G | 115.5 ± 3.2 | 36.3 ± 6.9 | 3.18 | 1.45 |
| U48A | 110.3 ± 2.2 | 37.2 ± 5.3 | 2.96 | 1.35 |
| Δ48 | 123.1 ± 4.7 | 34.9 ± 2.6 | 3.53 | 1.61 |
| G52A/C62G | 53.8 ± 3.2 | 11.5 ± 2.5 | 4.68 | 2.13 |
| U51A/A63U | 56.2 ± 4.9 | 8.8 ± 1.6 | 6.39 | 2.91 |
| U51G | <0.0001 | Nd | – | – |
| U48C/+G54 | <0.0001 | Nd | – | – |
Aminoacylation reactions were as described in Materials and Methods. Data presented here were the average of three independent experiments.
Nd, not determined.