Table 2.
Aminoacylation and pre-MSK-binding capacities of tRK1/tRK2 mutant transcripts
| RNA | Aminoacylation with [3H]lysine
|
Pre-MSK binding, %
|
|||
|---|---|---|---|---|---|
| Km, μM | Vmax, pmol/min | Vmax/Km | + KRS | − KRS | |
| 1 | 2.2 | 250 | 1.00 | 85 | 20 |
| 40 | 1.8 | 5 | 0.03 | 10 | 5 |
| 4 | 6.3 | 15 | 0.02 | 5 | 80 |
| 29 | 6.7 | 290 | 0.40 | 75 | 45 |
| 25 | 4.8 | 20 | 0.03 | 15 | 20 |
| 26 | 1.4 | 5 | 0.04 | 20 | 70 |
| 8 | 2.3 | 115 | 0.44 | 70 | 85 |
| 6 | 2.1 | 90 | 0.35 | 85 | 20 |
| 7 | 2.2 | 85 | 0.33 | 10 | <5 |
| 5 | 3.0 | 75 | 0.20 | 100 | 35 |
| 30 | 1.2 | 15 | 0.10 | 20 | 20 |
| 2 | 1.5 | 450 | 2.60 | 100 | 40 |
| 93 | 5.9 | 10 | 0.02 | 45 | 100 |
| 33 | 4.2 | 10 | 0.02 | 30 | <5 |
| tRK1 | 1.4 | 2,600 | 16.20 | 100 | 5 |
| tRK2 | 1.5 | 2,500 | 14.50 | <5 | 15 |
Pre-MSK binding of aminoacylated tRK1 was taken as 100%; values of nonspecific binding detected with preimmune antibodies have been subtracted. + KRS, in preaminoacylated form (preincubation with KRS and lysine); − KRS, without preincubation with KRS.