Role of the 8-double bond of lanosterol in the enzyme-substrate interaction of cytochrome P-450(14DM) (lanosterol 14 alpha-demethylase)

Biochim Biophys Acta. 1989 Feb 6;1001(2):196-200.

Abstract

The role of the 8-double bond of lanosterol in the enzyme-substrate interaction of yeast cytochrome P-450(14DM) (lanosterol 14 alpha-demethylase) was studied by analyzing metabolism of 8-lanostene-3 beta,32-diol, 7-lanostene-3 beta,32-diol, 6-lanostene-3 beta,32-diol and lanostane-3 beta,32-diol by the cytochrome. 8-Lanostene-3 beta,32-diol was actively metabolized by cytochrome P-450(14DM) and converted to the 32-nor-14-unsaturated metabolite. 7-Lanostene-3 beta,32-diol was also metabolized by the cytochrome, but the rate of metabolism was low. However, the cytochrome failed to catalyze the conversion of 6-lanostene-3 beta,32-diol and lanostane-3 beta,32-diol to their 32-nor metabolites. Spectral analysis of the sterol-cytochrome complexes and kinetics of cytochrome P-450(14DM) reduction in the presence of the sterols indicated that 6-lanostene-3 beta,32-diol and lanostane-3 beta,32-diol could not interact with the substrate site of the cytochrome. These results revealed that the 8-double bond of lanosterol plays an important role in the enzyme-substrate interaction of cytochrome P-450(14DM).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytochrome P-450 Enzyme System / metabolism*
  • Lanosterol / metabolism*
  • Models, Molecular
  • Oxidoreductases / metabolism*
  • Sterol 14-Demethylase

Substances

  • Lanosterol
  • Cytochrome P-450 Enzyme System
  • Oxidoreductases
  • Sterol 14-Demethylase