Table 5. Kinetic parameters for morphine-3-glucuronide and morphine-6-glucuronide catalyzed by UGT1A9*1-UGT2B7*N double recombinant allozymes.
| UGT1A9*1 -UGT2B7*N |
Km (μmol/L) |
Vmax (pmol·min−1·mg−1 protein) |
CLint (μL·min−1·mg−1 protein) |
CLint (M3G)/ CLint (M6G) | % of 2B7*1HA |
||||
|---|---|---|---|---|---|---|---|---|---|
| M3G | M6G | M3G | M6G | M3G | M6G | M3G | M6G | ||
| UGT1A9*1-CFP -UGT2B7*1-HA | 28.57±4.744 | 43.96±6.479* | 2425±159.0** | 1731±91.54** | 52.50** | 39.38** | 1.333 | 496.7 | 668.9 |
| UGT1A9*1-CFP -UGT2B7*71S-HA | 49.58±11.01** | 53.32±9.603 | 2682±222.3** | 1972±136.0** | 54.09** | 36.98** | 1.463 | 511.7 | 628.2 |
| UGT1A9*1-CFP -UGT2B7*2-HA | 52.73±8.907** | 64.91±11.01* | 2717±175.0** | 2315±161.0** | 51.53** | 35.66** | 1.445 | 487.5 | 605.7 |
| UGT1A9*1-CFP -UGT2B7*5-HA | 33.67±8.646 | 26.56±5.348** | 2410±201.8** | 1495±90.29** | 71.58** | 56.29** | 1.272 | 677.2 | 956.2 |
Kinetics analysis of UGT1A9*1-UGT2B7*N double recombinant allozymes mediate the glucuronide metabolism of morphine. Data are the mean±SD of three independent determinations, the asterisks indicate differences that are statistically significant compared to 2B7*1HA (*P<0.05; **P<0.01).