Apparent kinetic parameters for p-NP, dopamine, and 6-HM sulfations by His-ST1As
| Enzymes | p-NP | Dopamine | 6-HM | |||
|---|---|---|---|---|---|---|
| Km | Vmax | Km | Vmax | Km | Vmax | |
| μM | nmol/nmol/min | μM | nmol/nmol/min | μM | nmol/nmol/min | |
| ST1A5 (human) | >500 | N.D. | 14 | 5.06 | 65 | 18.08 |
| ST1A3 (human) | 3.0 | 3.98 | 130 | 3.98 | 18 | 11.94 |
| ST1A1 (rat) | 3.8 | 4.66 | 130 | 5.02 | 30 | 17.93 |
| St1a4 (mouse) | 3.2 | 4.04 | 98 | 6.24 | 40 | 18.34 |
| ST1A8 (rabbit) | 3.3 | 3.94 | >500 | N.D. | 29 | 17.90 |
Each parameter is derived from analysis of Lineweaver-Burk plots and shown as the mean of three separate experiments. Assays were performed at pH 7.4 with various concentrations of substrates (p-NP, 0.5–1000 μM; dopamine, 1–1000 μM; and 6-HM, 0.5–100 μM).
N.D., not determined.