Michaelis-Menten kinetic parameters determined for MPAG formation catalyzed by rat intestine microsomes
MPA UGT activities of microsomes prepared from the indicated intestinal segments of adult male Sprague-Dawley rats were analyzed as described under Materials and Methods, and kinetic parameters were determined. The Vmax/Km is included as a measure of intrinsic clearance. Results represent the average ± S.E.M. of three independent preparations.
Intestinal Segment | n | Km | Vmax | Vmax/Km |
|---|---|---|---|---|
| mM | nmol/mg/min | μl/mg/min | ||
| Duodenum | 3 | 0.067 ± 0.026 | 7.68 ± 0.29 | 180 ± 28 |
| S-1 | 3 | 0.056 ± 0.013 | 7.81 ± 1.56 | 143 ± 26 |
| S-2 | 3 | 0.091 ± 0.015 | 6.01 ± 0.37a | 70 ± 13a |
| S-3 | 3 | 0.160 ± 0.022a | 2.48 ± 0.43 | 16 ± 5 |
| S-4 | 3 | 0.103 ± 0.022 | 3.16 ± 0.40b | 33 ± 8b |
| Colon | 3 | 0.158 ± 0.004a, b | 3.20 ± 0.17b | 20 ± 1b |