Effect of TA on P450 content and residual DCMB hydroxylase activity for expressed P450 2B6 or human liver microsomes4-a
| Incubation Condition | [P450] | Residual Activity |
|---|---|---|
| nmol/mg | nmol/min/mg | |
| Expressed P450 2B6: | ||
| +acetonitrile, +NADPH | 0.12 (0.12, 0.12)4-b | 2.32 (2.30, 2.35) |
| +TA, −NADPH | 0.09 (0.10, 0.08) | 2.08 (2.24, 1.91) |
| +TA,+NADPH4-c | 0.04 (0.04, 0.04) | 0.70 (0.73, 0.67) |
| (38%)4-d | (32%) | |
| Human liver microsomes: | ||
| +acetonitrile, +NADPH | 0.41 (0.38, 0.43) | 1.20 (1.15, 1.24) |
| +TA, −NADPH | 0.46 (0.40, 0.51) | 0.96 (1.00, 0.92) |
| +TA,+NADPH4-e | 0.31 (0.34, 0.28) | 0.65 (0.63, 0.66) |
| (71%) | (60%) |
↵4-a Experimental details are given under Materials and Methods.
↵4-b Results are the average of duplicate determinations with individual values shown in parentheses.
↵4-c Heme levels decreased 38% compared with the +acetonitrile, +NADPH treatment.
↵4-d The percentage of spectrally-detectable P450 or activity remaining compared to the mean of the (+acetonitrile, +NADPH) and (+TA, −NADPH) controls.
↵4-e Remaining heme levels showed no decrease compared with the +acetonitrile, +NADPH treatment.