Recombination with lipids of the lipid-free protein from canine serum (d 1.063-1.2 1, α1) lipoprotein*

• Main Authors: Angelo Scanu, Irvine H. Page
• Format: Article
• Language: English
• Published: Elsevier 1961-04-01
• Series: Journal of Lipid Research
• Online Access: http://www.sciencedirect.com/science/article/pii/S0022227520390258

The protein (αP), prepared by delipidation of canine serum α1-lipoprotein (αLP), when labeled with I131 and injected into dogs, was metabolized at the same rate as native αLP, labeled in the protein moiety with I131. When αP-I131 was added to serum or injected into dogs, the radioactivity promptly appeared only in the αLP fraction, indicating a preferential interaction of the labeled protein with its own lipoprotein class. The nature of this interaction was not established. Mixing of αP-I131 with the low density lipoprotein class (βLP), in absence of serum, yielded two radioactive fractions, floating at d 1.063 and d 1.21. These two fractions had electrophoretic mobility similar to radioiodinated native °LP and αLP. In the absence of serum, αP-I131 reacted also with chylomicrons from serum or chyle. When the radioactive chylomicrons thus formed were injected into dogs, their disappearance from circulation paralleled that of an injected Lipomul (artificial triglyceride emulsion)-αLP-I131 complex. In both instances the disappearance of triglycerides was accompanied by appearance of radioactivity in the αLP fraction of plasma. When Lipomul was given intravenously to dogs injected with αLP-I131, it combined with a small amount of this labeled lipoprotein. The possible participation of αLP in the metabolism of triglycerides is briefly discussed.