RAPID MOLECULAR WEIGHT ESTIMATES FOR LOW-DENSITY LIPOPROTEINS

Molecular weight calculations from sedimentation velocity data require knowledge of shape, hydration, and density of the macromolecules. Reasonable values of shape and hydration for low-density serum lipoproteins are currently available. Uncertainty of calculated molecular weights resides mainly in uncertainty of lipoprotein density, especially if the density of the solution is close to that of the molecules. By the simple expedient of using high-density salt solutions (1.4-1.5 gm/ml) to float the lipoproteins, one can virtually eliminate the uncertainty in calculated molecular weight for a given uncertainty in lipoprotein density. This paper describes the high-salt flotation (HSF) technique for lowdensity lipoproteins and the calculation of molecular weights from such data. © 1969.