Enzyme kinetics of deferiprone glucuronidation by human tissue samples and UGT1A6 microsomal preparations
Kinetics from jejunum, ileum, and kidney (Hill equation) differed from those of UGT1A6 and from liver (Michaelis-Menten kinetic model).
Sample | Km | S50 | Absolute Vmax | Clint | Clmax | ||
|---|---|---|---|---|---|---|---|
| mM | nmol/min/mg protein | μl/min/mg | |||||
| Liver K22 | 10.0 ± 0.08 | 16.7 ± 1.7 | 1.7 | ||||
| Liver K23 | 8.0 ± 0.5 | 7.9 ± 2.7 | 1.0 | ||||
| Liver K24 | 7.6 ± 1.6 | 15.2 ± 4.1 | 2.0 | ||||
| Liver K25 | 9.3 ± 0.2 | 15.5 ± 1.7 | 1.7 | ||||
| Liver K26 | 8.9 ± 0.9 | 9.9 ± 0.8 | 1.1 | ||||
| Liver K27 | 8.5 ± 1.3 | 19.2 ± 3.7 | 2.2 | ||||
| Liver K28 | 8.3 ± 1.5 | 14.6 ± 0.2 | 1.8 | ||||
| Liver K29 | 9.2 ± 3.5 | 10.5 ± 2.9 | 1.2 | ||||
| Liver pool | 9.9 ± 0.5 | 19.3 ± 0.01 | 2.0 | ||||
| UGT1A6 * 1 | 10.0 ± 4.2 | 25.6 ± 3.2 | 3.0 | ||||
| Sample | |||||||
| Kidney | 5.3 ± 0.7 | 14.8 ± 1.5 | 1.4 | ||||
| Jejunum | 18.5 ± 6.8 | 1.5 ± 0.3* | 0.04 | ||||
| Ileum |
| 12.3 ± 1.7 | 1.0 ± 0.1* |
| 0.04 | ||
↵* Significantly different from human liver pool at P < 0.05.