Genetically engineered V79 chinese hamster cell expression of purified cytochromeP-450iib1 monooxygenase activity

✍ Scribed by Platt, K. L. ;Molitor, E. ;Döhmer, J. ;Dogra, S. ;Oesch, F.

• Book ID: 102874564
• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 546 KB
• Volume: 4
• Category: Article
• ISSN: 0887-2082
• DOI: 10.1002/jbt.2570040102

✦ Synopsis

Chinese hamster V79 fibroblasts, frequently used as target cells in short-term tests for mutagenicity, do not possess measurable monooxygenase activity; in particular, enzymatic oxidation of testosterone (T) cannot be demonstrated. If these V79 cells, however, had been transfected with the cDNAencoding rat liver cytochrome P-450IIBl under control of the SV40 early promoter, they stably expressed monooxygenase activity. These so-called SD1 cells then oxidatively metabolized T at a rate of 27 pmollmg proteinlmin, converting it to 16a-and 16B-hydroxy-T as well as 4-androsten-3,17-dione as sole metabolites in a ratio of 1.1:1.0:1.6. The regio-and stereoselective conversion of T by SD1 cells, as well as the quantitative distribution of the metabolites, corresponds well with the results reported for pure cytochrome P-450IIB1 in a reconstituted system.