Expression of bovine 17 alpha-hydroxylase cytochrome P-450 cDNA in nonsteroidogenic (COS 1) cells

Science. 1986 Dec 5;234(4781):1258-61. doi: 10.1126/science.3535074.


Cortisol production requires the activity of only 17 alpha-hydroxylase, whereas the formation of sex steroids requires both 17 alpha-hydroxylase and 17,20-lyase activities. Studies in reconstituted enzyme systems have suggested that a single steroid hydroxylase, 17 alpha-hydroxylase cytochrome P-450 (P-450(17) alpha), catalyzes both activities. By expression of bovine adrenocortical P-450(17 alpha) in COS 1 (transformed monkey kidney) cells, which normally contain no detectable P-450(17) alpha, it has now been established in situ that a single polypeptide chain does catalyze both the 17 alpha-hydroxylase and the 17,20-lyase reactions. This heterologous system supports 17 alpha-hydroxylation of pregnenolone and progesterone with equal efficiency, but catalyzes about five times as much 17,20-lyase activity when 17 alpha-hydroxypregnenolone is the substrate than when 17 alpha-hydroxyprogesterone is the substrate. For these activities to be observed in COS 1 cells, newly synthesized apocytochrome P-450(17) alpha must bind heme and insert into the endoplasmic reticulum such that endogenous cytochrome P-450 reductase can support hydroxylation. Thus, COS 1 cells are a useful system for expression and study of various forms of cytochrome P-450.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cattle
  • Chlorocebus aethiops
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism*
  • DNA / metabolism*
  • Fluorescent Antibody Technique
  • Kidney / cytology
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism
  • Pregnenolone / metabolism
  • Progesterone / metabolism
  • Steroid 17-alpha-Hydroxylase / metabolism*
  • Steroid Hydroxylases / genetics
  • Steroid Hydroxylases / metabolism*


  • Multienzyme Complexes
  • Progesterone
  • Pregnenolone
  • DNA
  • Cytochrome P-450 Enzyme System
  • Steroid Hydroxylases
  • Steroid 17-alpha-Hydroxylase