TABLE 2.
ESI LC-MS/MS analysis of CYP2E1 incubated with ad without reductase in the presence of PIC or PEITC
Incubations and separations were as described under Materials and Methods.
| Reaction system | Treatment | Observed Mass | Modifying Mass Unitd |
|---|---|---|---|
| P450 alone (control) | Methanol | 54838a | —– |
| P450 alone | 25 µM PEITC | 54838a | —– |
| P450 alone | 10 µM PIC | 54837a, 54982a | 145 |
| P450+reductase (control) methanol | 54843a | —– | |
| P450+reductase | 25 µM PEITC | 54842 ± 1b | —– |
| P450+reductase | 25µM PEITC+NADPH | 54843 ± 1c, 55018 ± 6c | 175 ± 6 |
ESI, electrospray ionization; LC-MS/MS, liquid chromatography-tandem mass spectrometry; PEITC, phenethyl isothiocyanate.
a
Data represent the mean of two injections in which the difference between the protein masses for the two injections was within three mass units.
b,cData represent the mean and standard deviations from three and four injections, respectively.
d
Difference in the protein mass between nonadducted and adducted peaks observed in each deconvoluted spectra.