Km values and turnover numbers of CHP and H2O2 for various substrates, determined by incubation of 0.2 μM CYP2S1 and fixed concentration of substrates
Data are represented as averages ± S.E. of duplicate determinations.
| Substrate | Product | CHP | H202 | ||
|---|---|---|---|---|---|
| Km | Turnover | Km | Turnover | ||
| μM | nmol product/nmol CYP2S1/min | μM | nmol product/nmol CYP2S1/min | ||
| Benzo[a]pyrene (167 μM) | 1,6-Dione | 16.1 ± 3.2 | 0.58 | 107 ± 21 | 0.44 |
| 3,6-Dione | 29.4 ± 5 | 1.36 | 215 ± 42 | 0.8 | |
| 6,12-dione | 30.8 ± 6 | 2.24 | 232 ± 46 | 1.46 | |
| 7,12-Dimethylbenz[a]anthracene (133 μM) | 7-OH-DMBA | 58.6 ± 11 | 15.7 | 4800 ± 950 | 15 |
| 12-OH-DMBA | 62.0 ± 12 | 26 | > 5000 | 14.8 | |
| 9,10-Dihydro-benzo[a]pyrene (50 μM) | 9,10H2-BaP-7,8-dihydrodiol | 188 ± 37 | 0.55 | 60 ± 12 | 0.13 |
| Benzo[a]pyrenetrans7,8dihydrodiol (133 μM) | r7,t8,t9,c10-tertol | 31.6 ± 5 | 1.1 | 1906 ± 350 | 0.3 |
| Aflatoxin B1 (243 μM) | Unknown | 8.8 ± 2 | N.D. | 3500 ± 700 | N.D. |
| Retinoic acid (20 μM) | 1.1 ± 0.4 | N.D. | 1.2 ± 0.4 | N.D. | |
N.D., not determined.