Table 1.
Comparison of Km, Kcat, and dynamic range of light-gated PDEs.
| Light-Gated PDEs | Km | Kcat, Vmax or Turnover | L/D Ratio | References |
|---|---|---|---|---|
| LAPD | Dark (cGMP): ~440 μM | Dark turnover (cGMP): ~ 42 s−1 | ~6 (cGMP) | [63] |
| 690 nm (cGMP): ~340 μM | Red 690 nm turnover (cGMP): ~252 s−1 | ~3.6 (cAMP) | ||
| Dark (cAMP): ~470 μM | Dark turnover (cAMP): ~30 s−1 | - | ||
| 690 nm (cAMP): ~180 μM | Red 690 nm turnover (cAMP): ~108 s−1 | - | ||
| Dr-BtPDE2A | - | Red 670 nm s−1 turnover (cGMP): ~225 s−1 | Red/far-red | [67] |
| Far-red 780 nm turnover (cGMP): ~38 s−1 | ~6 (cGMP) | |||
| SrRhoPDE | Dark (cGMP): ~80 μM | Dark turnover (cGMP): ~12 s−1 | 2–6 * (cGMP) | [71] |
| 473 nm (cGMP): ~13 μM | Blue 473 nm turnover (cGMP): ~28 s−1 | ~5 (cAMP) | ||
| MrRh-PDE | - | Dark (cGMP): ~600 pmol·min−1 # | ~1.1 (cGMP) | [74] |
| 520 nm (cGMP): ~672 pmol·min−1 # | ~1.7 (cAMP) | |||
| Dark (cAMP): ~145 pmol·min−1 # | - | |||
| 520 nm (cAMP): ~250 pmol·min−1 # | - |
* The ratio is changing depending on the substrate concentration. # Protein amount is not provided. For the other RhoPDEs, CfRh-PDE2, CfRh-PDE3, CpRh-PDE1, and CpRh-PDE2 showed no enzymatic activity. AsRh-PDE is specific for cAMP hydrolysis but without light-regulation. The activity of CfRh-PDE1 and CfRh-PDE4 was not significant [74]. Km: the michaelis constant; Kcat: number of substrate molecules turned into product per enzyme site per minute; Vmax: maximum velocity; L/D: light activity to dark activity.