Yeagle P L, Martin R B, Lala A K, Lin H K, Bloch K
Proc Natl Acad Sci U S A. 1977 Nov;74(11):4924-6. doi: 10.1073/pnas.74.11.4924.
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.
已比较了胆固醇、4,4-二甲基胆固醇和羊毛甾醇（4,4',14α-三甲基-δ8,24-胆甾二烯-3β-醇）对卵磷脂囊泡某些性质的影响。与胆固醇不同，羊毛甾醇仅略微延缓被困葡萄糖从磷脂囊泡中的流出。胆固醇/卵磷脂囊泡的13C核磁共振谱未显示出可归因于甾醇的共振信号。相比之下，在羊毛甾醇/卵磷脂囊泡的13C核磁共振谱中可看到几个可归因于季碳原子或甲基的共振信号，这表明羊毛甾醇的固定化程度远低于胆固醇。由于4,4-二甲基胆固醇的膜行为与胆固醇非常相似，因此得出结论，轴向的14-α-甲基基团导致羊毛甾醇的膜固定化程度降低。结果强调了平面甾醇α-面与磷脂酰链相互作用的重要性。
