TABLE 1

K_m values and turnover numbers of various substrates using purified synthetically encoded CYP2S1 (0.2 μM) and CHP (1 mM)

Data are represented as averages ± S.E. of duplicate determinations. K_m values were determined with Prism software using nonlinear regression with one site binding mode and the V = V_max · S/(K_m + S) equation. Turnovers were determined using the highest concentration of substrate.

Substrate	Product	K_m	Turnover
		μM	nmol product/nmol CYP2S1/min
Benzo[a]pyrene	1,6-Dione	94 ± 22	0.83
	3,6-Dione	48.6 ± 8	1.85
	6,12-Dione	72.7 ± 14	3.25
7,12-Dimethylbenz[a]anthracene	7-OH-DMBA	219 ± 4	15.7
	12-OH-DMBA	34 ± 9	26
9,10-Dihydro-benzo[a]pyrene	9,10H₂-BaP-7,8-dihydrodiol	22.6 ± 6	1.6
Benzo[a]pyrene-trans-7,8dihydrodiol	r7,t8,t9,c10-tertol	12.43 ± 2	2.3
Aflatoxin B1	Unknown	266 ± 40	N.D.
all-trans-Retinoic acid	4-OH-retinoic acid	20.9 ± 0.9	N.D.
Naphthalene	Unknown	N.D.	N.D.
Styrene	Unknown	N.D.	N.D.
Testosterone	No activity
Coumarin	No activity

N.D., not determined.