Purification and partial characterization of the apoA-I of rabbit high density lipoprotein

Purification of apoA-I from rabbit high density lipoproteins (HDL) gave one single band in sodium dodecylsulphate-polyacrylamide disc electrophoresis and reacted only with antiserum to apoA-I. The molecular weight was about 25000. The amino acid composition of rabbit ,poA-I gave a difference index of 7.4 compared to human apoA-I and of 6.5 compared to dog apoA-I. Of the three carboxy terminal amino acid residues the rabbit protein has one in common with the dog. The amino acid sequence of twenty-nine amino terminal residues showed 62% homology with the human protein; a minimum of thirteen base changes were required in the DNA sequences that encoded these two proteins. When the same sequence was compared with dog apoA-I, it was found that ten base changes would be sufficient to account for the differences between the proteins.