Partial specific volume and preferential hydration of low density lipoprotein subfractions.
We have determined the partial specific volume (v-) for five low density lipoprotein (LDL) subfractions (n = 5-7) and evaluated preferential hydration (n = 2) for LDL subfraction 3 in normolipoproteinemic subjects in order to characterize these highly atherogenic components of the human plasma lipoprotein spectra. Values for v- at 1 g were determined by sixth place density measurements of the solvent and lipoprotein solutions and carbon, hydrogen and nitrogen (CHN) absolute mass of the lipoprotein concentrations. Mean values for v- were 0.9757 +/- 0.0019, 0.9701 +/- 0.0007, 0.9674 +/- 0.0016, 0.9616 +/- 0.0016 and 0.9550 +/- 0.0025 ml/g for subfractions 1, 2, 3, 4 and 5, respectively. However, molecular densities (sigma) obtained from rho (rho) = 1/v- for respective LDL subfractions were 1.0249, 1.0308, 1.0337, 1.0399 and 1.0471 g/ml, respectively. The preferential hydration of lipoprotein subfraction 3 (n = 2) in NaCl/H2O solutions was 2.9-4.8 wt percent, whereas values were much lower (0.3-0.6 wt percent) in NaCl/NaBr/H2O solvent system. Unhydrated densities for LDL subfraction 3 (n = 2) at 1 g (sixth-place density meter) were 1.0287 and 1.0269 g/ml, whereas at 200,000 X g (used in D2O flotation eta F degrees vs rho determinations) both values were 1.0308 g/ml, indicating that these similar LDL fractions have 23 and 53% higher compressibility than the solvent at 200,000 X g force. It was observed that the linearity of eta F degrees vs rho may not be valid for solvents NaCl/NaBr/H2O of density as high as 1.4744 g/ml. Thus, flotation velocity data using extreme salt concentrations (1.4744 g/ml and higher) may be viewed with caution.
Kahlon
T S
TS
Adamson
G L
GL
Glines
L A
LA
Orr
J R
JR
Lindgren
F T
FT
D000328:Adult; D000368:Aged; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005260:Female; D006801:Humans; D006860:Hydrogen Bonding; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D008968:Molecular Conformation; D012016:Reference Values
D008077:Lipoproteins, LDL