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Biomedical subjects

R S Levy

Publications and source records attributed to R S Levy.

40 records · Page 3Linked to original sources
PubMed1968

Determination of the molecular weight of apoprotein subunits from low density lipoprotein by gel filtration.

Another method has been developed for obtaining a soluble apoprotein from the low density lipoprotein (LDL) of human plasma in the density class 1.019 < d < 1.063. The approximate molecular weight of the apoprotein subunit from this lipoprotein density class was determined by gel filtration on Sephadex G-200 to be about 80,000. Both on gel filtration and analytical ultracentrifugation the soluble apoprotein showed one peak, but on cellulose acetate electrophoresis it showed two bands, which suggests two differently charged components. Because of the nature of the determination, the value of 80,000 probably represents an upper limit to the molecular weight of the LDL subunits.

Chemical Phenomena↗
PubMed1967

Amino acid composition of the proteins from chylomicrons and human serum lipoproteins.

By a combination of polyanion precipitation and ultracentrifugation, chylomicrons, very low density, low density, and high density lipoproteins have been isolated from human serum as discrete classes free from contamination with any other major class of lipoprotein or protein. After removal of the lipid, the proteins from each class were hydrolyzed and their amino acid compositions were determined by use of the amino acid analyzer. Application of the "t" test to the concentrations of amino acid residues showed that the amino acid composition of the proteins from each of these lipoprotein classes differs significantly from class to class. However, when the logarithms of the moles of amino acid residues are plotted, there are similarities in the amino acid "profiles" between the chylomicrons and high density lipoproteins on the one hand, and between the very low density and low density lipoproteins on the other. The differences in amino acid composition between the lipoproteins suggest that any metabolic interconversions between them probably do not occur by simple lipolysis.

Amino Acids↗