title: Relation between lipid polymorphism and transbilayer movement of lipids in rat liver microsomes.
abstract: We have studied the effects of trinitrophenylation on the transbilayer movement of phosphatidylcholine and the macroscopic lipid structure in rat liver microsomal membranes. The transbilayer movement of phosphatidylcholine was investigated using the PC-specific transfer protein. 31P-NMR was employed to monitor the phospholipid organization in intact microsomal vesicles. The results indicate that modification of microsomes with trinitrobenzenesulfonic acid enhances the transbilayer movement of phosphatidylcholine at 4 degrees C. Furthermore, phosphatidylethanolamine headgroup trinitrophenylation in microsomes increases the isotropic component in the 31P-NMR spectra even at 4 degrees C, possibly representing the appearance of intermediate non-bilayer lipid structures. The observed parallel between these data suggests that phosphatidylethanolamine molecules in the microsomal membrane, probably in combination with a protein component, are able to destabilize the bilayer organization, thereby facilitating the transmembrane movement of phospholipids.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D007425:Intracellular Membranes / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines; D051381:Rats; D011919:Rats, Inbred Strains; D014302:Trinitrobenzenesulfonic Acid
chemical_list: D008051:Lipid Bilayers; D008563:Membrane Lipids; C027272:N-(2,4,6-trinitrophenyl)-phosphatidylethanolamine; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D014302:Trinitrobenzenesulfonic Acid