Genetically engineered V79 Chinese hamster cell expression of purified cytochrome P-450IIB1 monooxygenase activity

J Biochem Toxicol. Spring 1989;4(1):1-6. doi: 10.1002/jbt.2570040102.

Abstract

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 cDNA-encoding rat liver cytochrome P-450IIB1 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 pmol/mg protein/min, converting it to 16 alpha- and 16 beta-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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Chromatography, High Pressure Liquid
  • Cricetinae
  • Cricetulus
  • Cytochrome P-450 Enzyme System / biosynthesis*
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / isolation & purification
  • Genetic Engineering
  • Isoenzymes
  • Ketosteroids / metabolism
  • Male
  • Microsomes, Liver / enzymology
  • Microsomes, Liver / metabolism
  • Oxidation-Reduction
  • Oxygenases / biosynthesis*
  • Oxygenases / genetics
  • Oxygenases / isolation & purification
  • Phenobarbital / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Testosterone / metabolism
  • Transfection

Substances

  • Isoenzymes
  • Ketosteroids
  • Testosterone
  • Cytochrome P-450 Enzyme System
  • Oxygenases
  • Phenobarbital