Table 3. Kinetic parameters for quercetin-7-glucuronide by UGT1A9 double expression systems (n = 3).
| 1A9*N-1A9*N | Km (μmol/L) | Ksi (μmol/L) | Vmax (pmol/min/unit) | CLint (μL/min/unit) | % of 1A9*1-HA | % of 1A9*1-CFP |
|---|---|---|---|---|---|---|
| 1A9*1-CFP + 1A9*2-HA | 14.43 ± 1.09 | 519.0 ± 9.7 | 35.97** | 43.55 | 33.37 | |
| 1A9*1-CFP + 1A9*3-HA | 39.86 ± 9.74 | 254.0 ± 107.9 | 2977 ± 448.6 | 74.69* | 90.42 | 69.29 |
| 1A9*1-CFP + 1A9*5-HA | 31.97 ± 8.93 | 210.0 ± 91.6 | 1040 ± 173.0 | 32.53 | 39.38 | 30.18 |
| 1A9*2-CFP + 1A9*3-HA | 34.33 ± 5.82 | 675.0 ± 39.8 | 19.66** | 23.80 | 18.24 | |
| 1A9*2-CFP + 1A9*5-HA | 12.92 ± 1.24 | 145.7 ± 3.6 | 11.27*** | 13.64 | 10.45 | |
| 1A9*3-CFP + 1A9*5-HA | 34.66 ± 2.73 | 514.2 ± 14.2 | 14.8** | 17.92 | 13.73 |
*reprensts the CLint of double expression compared with that of the single expression with the two single expression plus together in the bracket. Data are the mean ± SD of three independent determinations, and the asterisks indicate differences that are statistically significant (***P < 0.001, **P < 0.005, *P < 0.05).