The Km and kcat for the metabolism of 7-EFC, bupropion, and efavirenz by CYP2B6 WT and CYP2B6.4 to CYP2B6.9 polymorphic variants
The Km and kcat values were obtained by fitting the data shown in Fig. 2 to the Michaelis-Menten equation as described under Materials and Methods. The reported Km and kcat were averages from two separate experiments, each of which was performed in duplicates.
| CYP2B6 | 7-EFC | Bupropion | Efavirenz | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Km | kcat | kcat/Km | Km | kcat | kcat/Km | Km | kcat | kcat/Km | |
| μM | min−1 | μM | min−1 | μM | min−1 | ||||
| CYP2B6.1 | 4.8 ± 1.1 | 1.2 ± 0.06 | 0.26 | 95 ± 15 | 6.8 ± 1.1 | 0.072 | 7.3 ± 2.2 | 4.0 ± 0.7 | 0.55 |
| CYP2B6.4 | 3.9 ± 0.42 | 0.52 ± 0.04 | 0.13 | 162 ± 32 | 4.1 ± 0.7 | 0.025 | 5.5 ± 0.8 | 2.9 ± 0.4 | 0.53 |
| CYP2B6.5 | 4.9 ± 1.9 | 0.89 ± 0.04 | 0.18 | 134 ± 7 | 4.5 ± 1.5 | 0.034 | 53 ± 12 | 40.2 ± 4.0 | 0.76 |
| CYP2B6.6 | 9.2 ± 2.1 | 1.7 ± 0.14 | 0.18 | 380 ± 27 | 11.9 ± 0.4 | 0.031 | 198 ± 28 | 22.5 ± 1.4 | 0.11 |
| CYP2B6.7 | 6.1 ± 2.1 | 1.0 ± 0.08 | 0.16 | 83 ± 10 | 4.7 ± 1.2 | 0.057 | 30.4 ± 5.0 | 26.3 ± 7.0 | 0.86 |
| CYP2B6.8 | N.D. | N.D. | N.D. | ||||||
| CYP2B6.9 | 7.0 ± 1.6 | 1.1 ± 0.07 | 0.16 | 244 ± 11 | 6.7 ± 0.9 | 0.027 | 57.5 ± 9.0 | 10.2 ± 2.0 | 0.18 |
N.D., not detected.