title: Sphingomyelin multiple phase behavior as revealed by multinuclear magnetic resonance spectroscopy.
abstract: 31P and 13C nuclear magnetic resonance (NMR) spectra are employed to study the phase behavior of bovine brain sphingomyelin as a function of temperature. The 31P NMR data suggest that, while at low temperatures sphingomyelin can form a lamellar phase, at physiological temperatures and higher the lamellar phase is unstable, and a new phase, best described as a hexagonal phase, is formed. Egg phosphatidylcholine is suggested to play an important role in stabilizing bilayers in natural membranes. Cholesterol also exhibits a sphingomyelin bilayer-stabilizing ability. The 13C NMR spectra suggest a gelling of the hydrocarbon chains of sphingomyelin at low temperature. Thus, bovine brain sphingomyelin undergoes both a gel to liquid-crystalline phase transition and a lamellar to nonlamellar transition.
mesh_terms: D000818:Animals; D001921:Brain; D002417:Cattle; D009682:Magnetic Resonance Spectroscopy; D008567:Membranes, Artificial; D008968:Molecular Conformation; D013109:Sphingomyelins; D013696:Temperature
chemical_list: D008567:Membranes, Artificial; D013109:Sphingomyelins