Apparent enzyme kinetic parameters for glucuronidation of galangin by HLM and recombinant UGT1A1, 1A9, and 2B15
| Peak 1 | Peak 2 | |||||
|---|---|---|---|---|---|---|
| Km | Vmax | Vmax/Km | Km | Vmax | Vmax/Km | |
| μM | pmol/min/mg | μl/min/mg | μM | pmol/min/mg | μl/min/mg | |
| HLM | 3.6 ± 0.7 | 1521 ± 252 | 427 ± 26 | 221 ± 31 | 34333 ± 2167 | 155 ± 30 |
| UGT1A9 | 1.1 | 721 | 655 | 31.8 | 3594 | 113 |
| UGT1A1 | N.D. | N.D. | N.D. | 6.3 | 388 | 62.1 |
| UGT2B15 | N.D. | N.D. | N.D. | 15.7 | 538 | 34.3 |
Data are means ± S.E. of three determinations for HLM and two for UGT isoforms. The velocity vs. substrate concentration curves are shown in Fig. 3.
HLM, human liver microsomes; N.D., activity not detectable.