Table 2.
Spectral binding constants and oxidation results observed for the studied chemicals with P450s 2A13 and 2A6
| chemical | P450 2A13 | P450 2A6 | ||
|---|---|---|---|---|
| Type I spectra a Ks (μM) |
metabolism b (HPLC) | Type I spectra a Ks (μM) |
metabolism b (HPLC) | |
| naphthalene | 0.35 ± 0.02 | yes | 2.9 ± 0.4 | yes |
| 2EN | 0.080 ± 0.04 | yes | 1.0 ± 0.1 | yes |
| 1NMPE | 13.3 ± 3.5 | not detected | 9.3 ± 1.8 | not done |
| 1NEPE | 1.1 ± 0.1 | yes | 11.5 ± 2.3 | not done |
| 2NPE | 0.42 ± 0.10 | yes | 33 ± 9 | not done |
| 2NMPE | 4.9 ± 0.6 | not detected | 21 ± 0 | not done |
| 2NEPE | 2.7 ± 0.6 | not detected | 19 ± 6 | not done |
| phenanthrene | 2.3 ± 0.2 | yes | 2.8 ± 0.4 | yes |
| 2EPh | 1.1 ± 0.3 | yes | 3.3 ± 0.4 | yes |
| 3EPh | 0.45 ± 0.08 | yes | 3.3 ± 0.9 | yes |
| 9EPh | 0.95 ± 0.08 | not detected | ND (10 μM) | not done |
| 2PPh | 3.9 ± 1.2 | yes | 1.6 ± 0.2 | yes |
| 3PPh | 1.2 ± 0.4 | yes | ND (10 μM) | not done |
| 9PPh | 6.4 ± 1.0 | not detected | 13 ± 3 | not done |
| biphenyl | 0.88 ± 0.16 | yes | 2.7 ± 0.5 | yes |
| 4EB | 1.9 ± 0.2 | not detected | 5.4 ± 0.5 | not detected |
| 4PB | 28 ± 12 | not detected | 7.0 ± 1.9 | not done |
| 4BuB | 3.4 ± 1.1 | not detected | 12 ± 2 | not done |
| 2BPE | 15.4 ± 1.7 | yes | 15 ± 2 | not done |
| 4BPE | 0.48 ± 0.06 | yes | 0.75 ± 0.16 | yes |
| 2BMPE | 1.7 ± 0.3 | not detected | 17 ± 3 | not done |
| 4BMPE | 66 ± 19 | not detected | 43 ± 33 | not done |
| 22BDPE | 11 ± 6 | not detected | 32 ± 9 | not done |
| 44BDPE | 6.5 ± 1.6 | not detected | 2.6 ± 0.8 | not detected |
a
Data reported are means and S.E. Analysis (HPLC) was used for monitoring metabolism. When peak(s) were detected only in the presence of an NADPH-generating system as described in Figure 8, metabolism results were marked as “Yes”. When no metabolite peaks were detected under these assay conditions, results were marked as “not detected”. Several of the chemicals were not examined with P450 2A6 (marked as “not done”).