| Literature DB >> 270726 |
P L Yeagle, R B Martin, A K Lala, H K Lin, K Bloch.
Abstract
The effects of cholesterol, 4,4-dimethylcholesterol, and lanosterol (4,4',14alpha-trimethyl-delta8,24-cholestadiene-3beta-ol) on some properties of lecithin vesicles have been compared. Unlike cholesterol, lanosterol retards the exit of trapped glucose from phospholipid vesicles only slightly. The 13C nuclear magnetic resonance spectrum of cholesterol/lecithin vesicles shows no resonances attributable to the sterol. By contrast, several resonances attributable to quaternary carbon atoms or methyl groups are seen in the 13C nuclear magnetic resonance spectrum of lanosterol/lecithin vesicles, indicating that lanosterol is much less immobilized than cholesterol. Because the membrane behavior of 4,4-dimethylcholesterol is closely similar to that of cholesterol, it is concluded that the axial 14-alpha-methyl group is responsible for the lessened membrane immobilization of lanosterol. The results emphasize the importance of a planar sterol alpha-face for interaction with phospholipid acyl chains.Entities:
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Year: 1977 PMID： 270726 PMCID： PMC432069 DOI： 10.1073/pnas.74.11.4924
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205