Table 2. Reverse Type I spectral changes and inhibition of EROD activities of human P450 1B1 with pyrenes, naphthalenes, phenanthrenes, and biphenyls.

	Reverse Type I spectra			inhibition of EROD
chemicals	Ks (μM)	ΔAmax	ΔAmax/Ks	IC50 (μM)
pyrene	1.3 ± 0.1	0.044 ± 0.001	0.0338	0.025 ± 0.003
1EP	2.9 ± 0.3	0.049 ± 0.005	0.0169	0.036 ± 0.005
2EP	3.4 ± 0.2	0.071 ± 0.001	0.0209	0.038 ± 0.004
4EP	4.0 ± 0.5	0.052 ± 0.004	0.0130	0.17 ± 0.03
1VP	4.4 ± 0.3	0.092 ± 0.003	0.0209	0.15 ± 0.02
1PP	2.7 ± 0.3	0.042 ± 0.002	0.0156	0.045 ± 0.005
naphthalene	ND	ND	ND	26 ± 3.2
2EN	15 ± 0.3	0.049 ± 0.002	0.0033	1.2 ± 0.2
1NMPE	92 ± 10	0.074 ± 0.005	0.0008	1.2 ± 0.3
1NEPE	88 ± 18	0.079 ± 0.009	0.0009	0.92 ± 0.15
2NPE	97 ± 19	0.086 ± 0.008	0.0009	4.3 ± 0.6
2NMPE	100 ± 17	0.090 ± 0.009	0.0009	2.1 ± 0.3
2NEPE	110 ± 3.1	0.094 ± 0.016	0.0009	5.2 ± 0.7
Phenanthrene	14 ± 1.7	0.044 ± 0.002	0.0031	0.51 ± 0.10
2EPh	4.2 ± 0.5	0.080 ± 0.004	0.0190	0.21 ± 0.03
3EPh	3.0 ± 0.3	0.071 ± 0.001	0.0237	0.16 ± 0.02
9EPh	3.6 ± 0.4	0.071 ± 0.004	0.0197	0.12 ± 0.01
2PPh	2.2 ± 0.2	0.067 ± 0.005	0.0305	0.15 ± 0.02
3PPh	3.1 ± 0.4	0.060 ± 0.006	0.0194	0.067 ± 0.008
9PPh	3.2 ± 0.4	0.049 ± 0.002	0.0153	0.16 ± 0.03
biphenyl	140 ± 19	0.037 ± 0.008	0.0003	19 ± 2.3
4EB	7.6 ± 1.2	0.023 ± 0.001	0.0030	2.2 ± 0.3
4PB	12 ± 1.8	0.074 ± 0.008	0.0062	1.8 ± 0.2
4BuB	54 ± 6.2	0.092 ± 0.007	0.0017	1.5 ± 0.3
2BPE	114 ± 16	0.110 ± 0.009	0.0010	15 ± 0.2
4BPE	83 ± 26	0.056 ± 0.010	0.0007	16 ± 0.3
2BMPE	146 ± 15	0.130 ± 0.009	0.0009	12 ± 0.2
4BMPE	13 ± 1.5	0.071 ± 0.002	0.0055	1.2 ± 0.1
22BDPE	30 ± 4.5	0.018 ± 0.001	0.0006	12 ± 1.7
44BDPE	23 ± 4.3	0.031 ± 0.002	0.0013	7.8 ± 1.0

ND, not detected at the highest concentration of 100 μM. K_s, ΔA_max, and IC₅₀ values presented are the means ± SEs obtained from the experiments with 5-8 different concentrations of the chemicals.