Kinetic parameters of UGT1A3 enzymes to quercetin (n = 3)
Assay was performed at 37°C for 10 min using 0.5 mg/ml protein. The concentrations of quercetin were 3.9 μM∼100 μM. The results are indicated as the mean ± S.D. from three independent expression experiments. The Km and Vmax values presented in this table represent a composite of all glucuronides formed using quercetin as substrate. Vmax and Vmax/Km are normalized by expression levels of recombinant UGT1A3 enzymes.
UGT1A3 Enzymes | Km | Vmax | Vmax/Km | Percentage of UGT1A3.1 |
|---|---|---|---|---|
| μM | pmol/min/mg | μl/mg/min | ||
| UGT1A3.1 | 39.40 ± 2.10 | 1974 ± 65 | 50.19 ± 1.42 | 100 |
| UGT1A3.2 | 16.34 ± 1.35 | 90.30 ± 1.19 | 5.55 ± 0.38 | 11 |
| UGT1A3.3 | 39.56 ± 1.64 | 450.9 ± 7.0 | 11.41 ± 0.30 | 23 |
| UGT1A3.4 | 21.00 ± 1.82 | 4877 ± 237 | 233.0 ± 15.9 | 464 |
| UGT1A3.5 | 11.05 ± 1.00 | 427.6 ± 31.6 | 38.76 ± 1.23 | 77 |