Table 3.
Reaction characteristics for the phosphorylation of rhodopsin mutants
| Mutant | Amino acid replacements by RK
|
||
|---|---|---|---|
| Vmax, pmol/min/μg RK | Km, μM | kcat/Km (s−1·M−1) | |
| WT | 39 ± 2 | 0.45 ± 0.04 | 9.2 × 104 (1.0) |
| CD-1 | 40 ± 1 | 0.34 ± 0.05 | 1.2 × 105 (1.3) |
| CD-2 | 19 ± 1 | 0.56 ± 0.09 | 3.6 × 104 (0.4) |
| CD-3 | 33 ± 2 | 0.40 ± 0.04 | 8.5 × 104 (0.9) |
| EF-1 | 35 ± 6 | 0.07 ± 0.01 | 5.1 × 105 (5.5) |
| EF-2 | 52 ± 3 | 0.32 ± 0.02 | 1.6 × 105 (1.7) |
| EF-3 | 24 ± 3 | 0.09 ± 0.01 | 2.8 × 105 (3.0) |
The Km values were calculated from Eadie–Hofstee plots derived from the data of Fig. 6. The Vmax values are from the rates of phosphorylation (data not shown). For the values of kcat/Km, kcat values are obtained from Vmax = kcat [E]0, where [E]0 is the amount of enzyme present in each time point aliquot.