Enzyme activities in total cellular protein isolated from various cell lines
| Cell Line | Cytochrome cReductase | Testosterone 6β-Hydroxylase |
|---|---|---|
| nmol/min/mg protein | pmol/min/mg protein | |
| MDR− | 6.1 ± 0.5 | N.D. |
| 3A4/HR/MDR− | 69.3 ± 2.8 | 15.5 ± 1.4 |
| 3A4/HR/MDR+ | 56.1 ± 1.9 | 11.0 ± 0.5 |
For isolation of total protein, cells were trypsinized and sonicated. Protein concentrations were determined as described underExperimental Procedures. The cytochrome creductase and the testosterone 6β-hydroxylase assay was performed at 37°C. Incubation time for the testosterone 6β-hydroxylase assay was 20 min. Assays were done in triplicate.
N.D., not detectable.