TABLE 5

Mass additions to CYP2A6 apoprotein from deconvoluted spectra of samples incubated with MCA, CA, and 8-MOP (N = 6 for all conditions)

Incubation Conditions	Theoretical Mass (Da)	Measured Mass (Da)	95% CI	Peak Area Ratio Adducted 2A6/2A6^{^a}	95% Cl
MCA + NADPH	162.19	156.79	142.54–171.04	0.24^{^b}	0.15–0.32
MCA − NADPH	162.19	151.66	136.88–166.44	0.13	−0.001 to 0.14
CA + NADPH	132.16	132.67	123.37–141.98	0.26^{^b}	0.14–0.37
CA − NADPH	132.16	127.61	118.56–136.65	0.13	0.07–0.18
8-MOP + NADPH	216.19 232.19	247.97	235.70–260.24	0.59	0.42–0.75
2A6 + NADPH^{^c}	N/A	N/A	N/A	N/A	N/A

↵^a Peak area_{(CYP2A6 mass + inhibitor mass)}/peak area_{(CYP2A6 mass)}.
↵^b P = 0.003 (MCA); P = 0.025 (CA); comparison with CYP2A6 with inhibitor minus NADPH.
↵^c N/A indicates 'not applicable' as a deconvoluted peak corresponding to covalently modified CYP2A6 was not observed in these samples.