The effect of dolichol on the permeability properties of phosphatidylcholine bilayers.
The permeability of liposomes to water, glucose, Ca2+ and alkaline cations was monitored by recording the change in absorbance at 450 nm using a rapid reaction stopped-flow spectrophotometer. Liposomes were prepared with egg phosphatidylcholine and concentrations of dolichol ranging from 0.1% to 9% (w/w). Net permeability of phosphatidylcholine bilayers to alkaline cations was induced by the incorporation of dolichol. This effect was not observed in the case of non-charged solutes like glucose or in that of alkaline earth cations such as calcium. Permeation of K+ was significantly increased above the phase transition temperature. These results suggest that dolichols may play a role in biological membranes, besides the well-known glycosyl carrier function in the biosynthesis of glycoproteins.
D002118:Calcium; D004224:Diterpenes / Q000032:analysis*; D004286:Dolichols / Q000032:analysis*; D005947:Glucose / Q000032:analysis; D008051:Lipid Bilayers / Q000032:analysis*; D008081:Liposomes / Q000032:analysis; D010539:Permeability; D010713:Phosphatidylcholines / Q000032:analysis*; D011188:Potassium / Q000032:analysis; D013696:Temperature
D004224:Diterpenes; D004286:Dolichols; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D005947:Glucose; D011188:Potassium; D002118:Calcium