Table 1.
Kinetic Parameters of ROS Phosphorylation for GRK αN Variantsa
| bGRK1 variants | kcat (×10−3 s−1) | KM (×10−6 M) | kcat/KM (×103 M−1 s−1) | fold decrease (kcat/KM) | hGRK6 variants | fold decreaseb (kcat/KM) |
|---|---|---|---|---|---|---|
| wt | 25 ± 4 | 3.4 ± 1.7 | 7.2 ± 2.7 | 1 | wt | 1 |
| L6A | 4.9 ± 0.4 | 12 ± 3 | 0.40 ± 0.05 | 18 | L3A | 2 |
| E7A | 7.7 ± 0.6 | 13 ± 2 | 0.62 ± 0.07 | 12 | E4A | 3 |
| V9A | 2.2 ± 0.3 | 18 ± 5 | 0.13 ± 0.02 | 55 | I6A | 12 |
| V10A | 1.2 ± 0.3 | 21 ± 9 | 0.057 ± 0.013 | 130 | V7A | 13 |
| A11E | 22 ± 1 | 8.8 ± 1.2 | 2.5 ± 0.2 | 3 | ||
| N12A | 1.7 ± 0.7 | 20 ± 15 | 0.083 ± 0.032 | 87 | N9A | 140 |
| F15A | 3.5 ± 0.6 | 11 ± 5 | 0.32 ± 0.08 | 23 | L12A | 1100 |
| I16A | 11 ± 2 | 9.5 ± 4.8 | 1.1 ± 0.4 | 7 | L13A | 6 |
| A18E | 8.7 ± 0.7 | 6.1 ± 1.4 | 1.4 ± 0.2 | 5 |
a
Numbers shown represent means ± the standard error of the fit calculated from three to six independent experiments. Reactions were performed in 100 mM HEPES-NaOH (pH 7.5), 0.15 M NaCl, 10 mM MgCl2, and 1 mM EDTA for <5 min at room temperature.
b
Data taken from ref 15.