Metabolism of the Protein Moiety of Rabbit Serum Lipoproteins

Abstract

Summary

Alanine-1-C¹⁴ was administered to rabbits and its incorporation into the lipoproteins of D< 1.063 and D 1.063 − 1.21 fractions and into the remaining serum proteins was measured. The D< 1.063 fraction reached a higher specific activity than did the D 1.063−1.21 lipoprotein fraction or the D>1.21 fraction. Both lipoprotein fractions turned over at a faster rate than did the remaining serum proteins. C¹⁴-labeled lipoprotein fractions were injected into rabbits and there was no significant interconversion between the two major density classes of lipoproteins studied. These data suggest that the D< 1.063 and D 1.063 − 1.21 classes of lipoproteins are metabolically as well as chemically distinct.