Kinetic parameters for the glucuronidation of Tacro by human tissues and UGT1A4 variant allozymes
Results are expressed with mean ± S.D. of triplicate determinations of three independents experiments.
| Apparent Km | Vmaxa | Vmax/Km | |
|---|---|---|---|
| μM | area · min−1 · mg−1 | μl · min−1 · mg−1 | |
| UGT1A4 allozymes | |||
| 1A4*1 (R11P24L48) | 91 ± 28 | 1.65 ± 0.34 | 0.018 |
| 1A4*2 (Thr24) | 114 ± 29 | 1.65 ± 0.31 | 0.014 |
| 1A4*3 (Val48) | 126 ± 51 | 2.23 ± 0.37 | 0.018 |
| 1A4*4 (Trp11) | 101 ± 48 | 3.14 ± 0.51* | 0.030 |
| Individual liver samples (UGT1A4 status) | |||
| K28 (*1/*1) | 41.2 ± 1.5 | 0.32 ± 0.03 | 0.008 |
| K29 (*1/*1) | 33.5 ± 8.6 | 0.33 ± 0.02 | 0.010 |
| K21 (*1/*2) | 52.8 ± 6.6 | 0.28 ± 0.02 | 0.005 |
| K22 (*1/*2) | 39.4 ± 5.1 | 0.29 ± 0.02 | 0.007 |
| K14 (*1/*3) | 36.8 ± 8.4 | 1.03 ± 0.10 | 0.028 |
| K23 (*1/*3) | 38.7 ± 7.2 | 0.36 ± 0.03 | 0.009 |
| Intestine pool | 51.8 ± 5.7 | 0.04 ± 0.01 | 0.001 |