TABLE 1

Activities of different human P450 enzymes in the metabolism of nicotine and PhIP

The activities were expressed as pmol of metabolite formation/min/pmol of P450. For nicotine metabolism, the activity was determined by cotinine formation, and the values are mean ± S.D. of three separate experiments. For PhIP metabolism, the activity was determined by N-hydroxy PhIP formation, and the results are the average of duplicate experiments.



Substrate Concentration
P450 Nicotine
PhIP (200 μM)

10 μM
100 μM
2A6 0.70 ± 0.12 4.01 ± 1.25
2A13 5.15 ± 1.29 18.97 ± 2.25
1A2 6.57
2S1
N.D.
N.D.
N.D.
  • N.D., not detectable; —, not determined.