ASSESSMENT OF CHOLESTERYL ESTER TRANSFER PROTEIN FUNCTION IN LIPOPROTEIN MIXTURES BY H-1-NMR SPECTROSCOPY

Studies of cholesteryl ester transfer protein (CETP) function in lipop rotein mixtures pose many difficulties by conventional biochemical met hods, For instance, studies on the effects of CETP on the composition of apolipoprotein B containing lipoproteins (very low and low density lipoproteins) in lipoprotein mixtures are tedious due to repeated ultr acentrifugation isolations and have thus rarely been performed, Here w e present a new H-1 NMR spectroscopy technique to assess the CETP func tion in Lipoprotein mixtures, This technique does not require repeated physical isolations of the lipoprotein particles but uses mathematica l separation of the fractions on the basis of biochemical prior knowle dge based lineshape fitting analysis of specific lipid resonances in t he H-1 NMR spectra, The lipoproteins are separated according to their size related chemical shift which allows for distinct quantification b etween very low and low density Lipoproteins, the two major apolipopro tein B containing fractions, The methodological basis of the technique is discussed here together with a demonstration that this kind of app roach allows dynamic follow up of the lipid transfer reactions in comp lex lipoprotein and CETP mixtures, The results revealed a consistent b ehaviour which corroborated the recent findings suggesting that the ne utral lipid mass transfer among lipoproteins is not an equimolar heter oexchange (J, Lipid Res, 36, 2574-2579, 1995). (C) 1997 John Wiley & S ons, Ltd.