13C-NMR Spectroscopy of Human Serum High Density Lipoprotein Enriched with Labelled Phospholipids

Abstract
Native human serum high density lipoprotein (HDL) (density = 1.063-1.21 g .times. cm-3) was enriched with phosphatidylcholines labeled with 13C in the polar head group ([N-13CH3]choline) and in the fatty acyl chains ([26-13C]cholesterol) and its linoleic acid ester using the previously described exchange method (Stoffel et al.). The properties of the HDL particles with the exchanged lipid classes were the same as those of the native particles (MW, circular dichroism, fluorescence, lipid and apoprotein stoichiometry, electrophoretic mobility). The T1 times were very similar to those obtained previously with recombined apolipoprotein-[13C]lipid complexes.