TABLE 3.

CYP2A6-catalyzed [³H]nicotine Δ^5′(1′)iminium ion metabolism

CYP2A6 (25 pmol) was incubated with 5 μM(4 μCi/nmol) [³H]nicotine Δ^5′(1′)iminium ion at 30°C. At the indicated times aliquots were analyzed on HPLC system II as described under Materials and Methods. The values reported are the mean ± S.D. for four independent experiments.

Time	Percentage of Radioactivitya				Ratio
	Iminium Ion	Cotinine	NCOT and NHCOTb	3HCOTc	cis-3HCOT/trans-3HCOT	3HCOTc/NCOT and NHCOT
2.5 min	85 ± 5	4 ± 1	2 ± 0.5	2 ± 1	0.4 ± 0.2	1.0 ± 0.4
5 min	77 ± 3	7 ± 2	5 ± 1	3 ± 1	0.3 ± 0.04	0.6 ± 0.2
10 min	64 ± 3	11 ± 2	10 ± 2	4 ± 1	0.3 ± 0.2	0.5 ± 0.2
20 min	50 ± 6	15 ± 1	19 ± 2	6 ± 2	0.2 ± 0.1	0.3 ± 0.1

^a Percentage of the sum of all metabolites and the nicotine Δ^5′(1′)iminium ion quantified by HPLC.

^b Sum of NHCOT and NCOT.

^c Sum of cis- and trans-isomers 3HCOT.