Partitioning behaviour of 1-hexanol into lipid membranes as studied by deuterium NMR spectroscopy.
Deuterium nuclear magnetic resonance (NMR) spectroscopy was used to study the partitioning behaviour of 1-hexanol specifically deuterated in the alpha-position into model lipid bilayers. In all systems studied, the observed deuterium NMR lineshapes were time-dependent. Initially, 1-hexanol-d2 gave rise to an isotropic deuterium resonance with a different chemical shift from that of aqueous 1-hexanol-d2. After equilibration over a period of days, a broader spectral component characteristic of a spherically-averaged powder-pattern was observed. The quadrupole anisotropy of the 1-hexanol-d2 giving rise to the broad spectrum depended upon the cholesterol content of the membrane. From quantitation of the anisotropic to isotropic deuterium NMR spectra, the partition coefficients of 1-hexanol-d2 in a number of bilayer systems (asolectin and phosphatidylcholine bilayers (the latter with and without cholesterol] were determined. The partitioning of 1-hexanol-d2 into red blood cell membranes, and a suspension of lipids extracted from red blood cell membranes, was also examined. It is suggested that 1-hexanol, and probably other lipophiles, can partition to either the bilayer surface or the bilayer interior in a time-dependent manner.
Fraser
D M
DM
Department of Biochemistry, University of Oxford, U.K.
Van Gorkom
L C
LC
Watts
A
A
D003903:Deuterium; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004910:Erythrocyte Membrane / Q000737:chemistry*; D000441:Hexanols / Q000737:chemistry*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000097:blood; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013535:Suspensions
D000441:Hexanols; D008051:Lipid Bilayers; D008055:Lipids; D013535:Suspensions; C036260:1-hexanol; D003903:Deuterium; D004134:Dimyristoylphosphatidylcholine