Table 1. NNK reduction and its metabolites by a CYP2A13- and 2A6-catalyzed reaction a .
| Control (μM) | 2A13 (μM) | 2A6 (μM) | |
| NNK | 10.41 ± 0.20 | 4.33 ± 0.29 | 10.04 ± 0.20 |
| OPB | 0 | 0.96 ± 0.032 | — b |
| HPB | 0 | 1.76 ± 0.012 | — b |
| OPBA | 0 | 0.46 ± 0.015 | — b |
aIndicates that the enzymatic reaction was performed at 37 °C for 10 min with 25 pM CYP2A13 (or 50 pM CYP2A6), 10 μM NNK, NADPH-generating system and 3 mM MgCl2 in 0.1 mM Tris buffer at pH 7.4. Values are means ± SD (n = 3).
bRepresents the metabolites level was under the limit of quantitation in the recent analytical method.