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Digitonide precipitable sterols: A reevaluation with special attention to lanosterol
Author(s) -
Cenedella Richard J.
Publication year - 1982
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02535224
Subject(s) - lanosterol , cycloartenol , digitonin , sterol , chemistry , desmosterol , cholesterol , lipidology , clinical chemistry , chromatography , biochemistry , enzyme
The ability of digitonin to precipitate lanosterol from prepared mixtures and biological sources was evaluated. Commercially available lanosterol was determined to be composed of about 60% lanosterol and 40% dihydrolanosterol. Both sterols were only partially precipitated by digitonin under all conditions examined. The presence of cholesterol increased the precipitation of lanosterol, but never to completion. About 40% of the lanosterols from saponified sheep's‐wool fat was not precipitated by digitonin. Also 14 C‐labeled lanosterol recovered from rat brain following intracerebral injection of 2‐[ 14 C] mevalonate was only 70% precipitated by digitonin. Steric hinderance by the methyl groups at carbon −4 is suggested to explain the poor precipitability of this sterol. In conclusion, lanosterol can not be considered to be a digitonide‐precipitable sterol equivalent to cholesterol. Caution should be exercised in situations where digitonin‐precipitable sterols are being prepared from sources containing significant concentrations of lanosterol (i.e., mass and/or radiolabel).