Partial purification of 2,3-oxidosqualene-lanosterol cyclase from hog-liver. Evidence for a functional thiol residue

Biochem Biophys Res Commun. 1988 Mar 30;151(3):1378-85. doi: 10.1016/s0006-291x(88)80515-1.


2,3-Oxidosqualene-lanosterol cyclase is an intrinsic microsomal protein which can be solubilized by ionic (deoxycholate) and nonionic (emulphogene) detergents with good yields. The hog-liver microsomal cyclase was purified approximately 140-fold by chromatography on DEAE-cellulose and hydroxylapatite. The partially purified enzyme was inactivated by N-ethylmaleimide, following pseudo-first order kinetics, indicating that a cysteine residue is essential for activity.

MeSH terms

  • Animals
  • Deoxycholic Acid / pharmacology
  • Ethylmaleimide / pharmacology
  • Intramolecular Transferases*
  • Isomerases / analysis
  • Isomerases / isolation & purification*
  • Male
  • Microsomes, Liver / enzymology*
  • Molecular Weight
  • Solubility
  • Sulfhydryl Compounds / analysis*
  • Swine


  • Sulfhydryl Compounds
  • Deoxycholic Acid
  • Isomerases
  • Intramolecular Transferases
  • lanosterol synthase
  • Ethylmaleimide