Table 2
Metabolism of NNK and MTBE by heterologously expressed human CYP2A6 and CYP2A13
Metabolism of NNK and MTBE was assayed as described in “Materials and Methods.” NNK (10 μm) and MTBE (0.25 mm)were incubated with the reconstituted CYPs at 37°C for 15 or 30 min,respectively. Where indicated, the molar ratio of CYP b5 was 1
4. The values reported are the average of two separate determinations with variations of<10% of the mean.
| Enzyme | Rate of product formation (nmol/min/nmol CYP) | ||||
|---|---|---|---|---|---|
| NNK | MTBE | ||||
| Keto aldehyde | Keto alcohol | tert-butyl alcohol | |||
| CYP2A13 | 1.8 | 0.45 | 1.1 | ||
| CYP2A13+ b5 | 2.2 | 0.62 | 1.4 | ||
| CYP2A6 | 0.024 | n.d.a | 1.1 | ||
| CYP2A6+ b5 | 0.036 | n.d. | 1.1 | ||
| Enzyme | Rate of product formation (nmol/min/nmol CYP) | ||||
|---|---|---|---|---|---|
| NNK | MTBE | ||||
| Keto aldehyde | Keto alcohol | tert-butyl alcohol | |||
| CYP2A13 | 1.8 | 0.45 | 1.1 | ||
| CYP2A13+ b5 | 2.2 | 0.62 | 1.4 | ||
| CYP2A6 | 0.024 | n.d.a | 1.1 | ||
| CYP2A6+ b5 | 0.036 | n.d. | 1.1 | ||
a
n.d., not detected.