1H NMR studies of human blood plasma. Assignment of resonances for lipoproteins.

Single-pulse and Hahn spin-echo 500 MHz 1H NMR spectra of human blood plasma and isolated chylomicrons, VLDL, LDL and HDL are reported. The comparison has enabled specific assignments to be made for the resonances of individual lipoproteins in the CH2 and CH3 (fatty acid), and NMe+3 (phospholipid choline head group) regions of the spectra of plasma (0.8-1.3 and approximately 3.25 ppm, respectively). Fasting, and freeze-thawing of plasma samples led to marked changes in the intensities and linewidths of lipid resonances. Analysis of lipid resonances in the spectra of plasma in terms of individual lipoproteins may shed new light on many conditions of clinical and biochemical interest.